Break-even units = fixed costs / (price per unit - variable cost per unit)Worked example
With 10,000 fixed cost, price 100, and variable cost 60, break-even is 250 units.
Calculation methodology dataset
Calculator Formula Library
Search the formulas behind Calxo AI calculators, read a worked example, see the important caution, and open the interactive calculator. The library spans everyday arithmetic, finance, health, business, construction, physics, statistics, chemistry, food, travel, and more.
Updated June 23, 2026 · Version 2026.06.23
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Formulas and worked examples
283 formulas
Runway months = cash balance / monthly net burnWorked example
300,000 cash and 50,000 monthly burn gives 6 months runway.
Churn rate = lost customers / starting customers x 100Worked example
50 lost customers from 1,000 starting customers is a 5% churn rate.
Conversion rate = conversions / visitors x 100Worked example
120 conversions from 4,000 visitors is a 3% conversion rate.
CPM = spend / impressions x 1000; CPC = spend / clicks; CTR = clicks / impressionsWorked example
500 spend on 100,000 impressions has a CPM of 5.
CLV = average order value x purchases/year x lifespan x gross marginWorked example
100 order value x 4 purchases x 3 years x 60% margin = 720.
Annual depreciation = (cost - salvage value) / useful lifeWorked example
A 10,000 asset with 1,000 salvage over 5 years depreciates by 1,800 per year.
Sale price = original price x (1 - discount / 100)Worked example
A 25% discount on 200 saves 50 and gives a sale price of 150.
EBITDA = revenue - COGS - operating expenses + D&A; margin = EBITDA / revenueWorked example
500,000 revenue and 100,000 EBITDA gives a 20% margin.
Deadline = received time + SLA hoursWorked example
A 4-hour SLA from 09:30 is due by 13:30.
Day rate = target income x (1 + overhead %) / billable daysWorked example
120,000 target income with 20% overhead over 180 billable days is 800/day.
Gross profit = revenue - COGS; gross margin = gross profit / revenueWorked example
100,000 revenue and 60,000 COGS gives 40% gross margin.
Total hiring cost = fees + ads + interview time + onboarding + ramp costWorked example
Add direct and time-based costs to estimate cost per hire.
Inventory turnover = COGS / average inventoryWorked example
250,000 COGS and 45,000 average inventory gives 5.56 turns.
Total = (subtotal - discount) x (1 + tax rate)Worked example
1,000 minus 50 discount plus 8% tax totals 1,026.
Selling price = cost x (1 + markup / 100)Worked example
If cost is 60 and markup is 50%, selling price is 90 and gross profit is 30.
Cost = attendees x hours x hourly costWorked example
8 people for 1.5 hours at 60/hour costs 720.
Business
Pakistan Sales Tax Return Calculator calculation method
Pakistan Sales Tax Return CalculatorPakistan Sales Tax Return Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative business scenario for Pakistan, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
Unit price = total price / quantityWorked example
12.50 for 5 kg is 2.50 per kg.
Margin = (price - cost) / price x 100; Markup = (price - cost) / cost x 100Worked example
If cost is 60 and price is 100, profit is 40, margin is 40%, and markup is 66.67%.
Quick ratio = (cash + receivables + marketable securities) / current liabilitiesWorked example
125,000 quick assets and 90,000 liabilities gives a ratio of 1.39.
Reorder point = demand per day x lead time + safety stockWorked example
120 units/day for 7 days plus 300 safety stock gives 1,140 units.
ROI = (gain - cost) / cost x 100Worked example
A 1,500 gain on 1,000 cost is 50% ROI.
Commission = sales x rate; payout = commission + bonusWorked example
50,000 sales at 8% plus 500 bonus pays 4,500.
Tax = price x tax rate / 100; total = price + taxWorked example
At 8% tax, a 100 price has 8 tax and a total of 108.
Business
Singapore Corporate Income Tax Calculator calculation method
Singapore Corporate Income Tax CalculatorSingapore Corporate Income Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative business scenario for Singapore, review every editable rule, and compare the estimate with current official guidance for 2026.
Hours = end time - start time - breakWorked example
09:00 to 17:30 with a 30-minute break is 8 hours.
Business
UAE Import Duty and Landed Cost Calculator calculation method
UAE Import Duty and Landed Cost CalculatorUAE Import Duty and Landed Cost Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative business scenario for UAE, review every editable rule, and compare the estimate with current official guidance for 2026.
UAE VAT Return Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative business scenario for UAE, review every editable rule, and compare the estimate with current official guidance for 2026.
Working capital = current assets - current liabilitiesWorked example
180,000 assets and 120,000 liabilities gives 60,000 working capital.
C1V1 = C2V2Worked example
25 mL of 10x stock diluted to 250 mL gives 1x final concentration.
PV = nRT; P = nRT / VWorked example
1 mol at 298.15 K in 24.5 L is close to 1 atm.
Molarity = moles of solute / liters of solutionWorked example
0.5 mol in 1 L gives 0.5 M.
pH = -log10([H+])Worked example
1e-6 mol/L hydrogen ion concentration gives pH 6.
Area = length x widthWorked example
A room 5 m long and 4 m wide has area 20 square meters.
Bricks = wall area / brick face area x waste factorWorked example
Wall area divided by brick face area gives an estimated brick count.
Cost = length x width x depth x unit priceWorked example
A 5 m by 4 m slab at 0.1 m depth needs about 2 cubic meters.
Volume = length x width x depthWorked example
A 5 m by 4 m slab at 0.1 m depth needs 2 cubic meters of concrete.
Rows = deck width / board spacing; total boards = rows x boards per row x waste factorWorked example
A 16 by 12 ft deck with 5.5 inch boards can be estimated by rows and board lengths.
Sheets needed = ceil(wall area x (1 + waste %) / sheet area)Worked example
500 sq ft with 4 x 8 sheets and 10% waste needs about 18 sheets.
Posts = floor(length / spacing) + 1Worked example
100 ft at 8 ft spacing needs about 13 posts.
Material area = floor area x (1 + waste %); cost = material area x unit priceWorked example
50 sq m with 8% waste needs 54 sq m of material.
Volume = length x width x depth; tonnes = volume x density / 1000Worked example
A 5 m by 4 m area at 10 cm depth needs about 2 cubic meters before waste.
Board feet = thickness(in) x width(in) x length(ft) x pieces / 12Worked example
2 x 6 x 8 x 10 pieces equals 80 board feet.
Cubic feet = area in square feet x depth in inches / 12Worked example
240 sq ft at 3 inches deep needs 60 cubic feet before waste.
Paint needed = wall area x coats / coverage per literWorked example
80 sq m at 10 sq m per liter for 2 coats needs about 16 liters.
Pavers = area / paver area x waste factorWorked example
200 sq ft with 8 by 4 inch pavers needs about 900 pavers before pattern effects.
Roof area = plan area x pitch factor x (1 + waste %)Worked example
100 sq m plan area with 1.12 pitch factor and 10% waste needs about 123.2 sq m.
Risers = ceil(total rise / preferred riser height); run = (risers - 1) x tread depthWorked example
108 inches total rise at 7.5 inches gives 15 risers.
Tiles needed = floor area x (1 + waste %) / tile areaWorked example
For 20 sq m with 0.36 sq m tiles and 10% waste, buy about 62 tiles.
Items needed = wall area / coverage per itemWorked example
A 240 sq ft wall with 30 sq ft rolls needs 8 rolls before waste.
Age = comparison date - date of birth, adjusted by calendar months and daysWorked example
If birth date is 20 May 2000 and comparison date is 20 May 2026, the age is exactly 26 years.
Count Monday-Friday dates between start and endWorked example
Weekends are excluded; holidays are not.
Days remaining = target date - todayWorked example
A negative result means the selected date has already passed.
Difference = end date - start dateWorked example
From 1 January 2026 to 31 January 2026 is 30 elapsed days.
Target date = today + number of daysWorked example
30 days from 20 May 2026 is 19 June 2026.
Duration = end time - start timeWorked example
From 09:30 to 17:15 is 7 hours 45 minutes.
Selected local time is mapped to an instant, then formatted in the target timezoneWorked example
12:00 in America/New_York converts using the daylight saving rule for the selected date.
Local time = UTC instant formatted in selected timezoneWorked example
12:00 UTC becomes evening in Asia/Kolkata and morning in New York depending on DST.
Week is calculated from the nearest Thursday in the ISO week yearWorked example
Early January dates can belong to the last ISO week of the previous year.
Education
Australia HELP Repayment Calculator calculation method
Australia HELP Repayment CalculatorAustralia HELP Repayment Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative education scenario for Australia, review every editable rule, and compare the estimate with current official guidance for 2026/27.
Fraction = decimal x denominator / denominator, then simplifyWorked example
0.75 = 75/100 = 3/4.
GPA = sum(credits x grade points) / total creditsWorked example
Courses worth 3, 3, 4, and 2 credits with grade points 4.0, 3.7, 3.3, and 4.0 give a GPA of about 3.67.
Needed final score = (target - current x (1 - final weight)) / final weightWorked example
With an 84 current grade, 90 target, and 30% final, you need 104% on the final.
Needed = (target - current x completed weight) / remaining weightWorked example
If 70% is completed at 62 and target is 60, the final needed is about 55.3.
Education
New Zealand Student Loan Repayment Calculator calculation method
New Zealand Student Loan Repayment CalculatorNew Zealand Student Loan Repayment Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative education scenario for New Zealand, review every editable rule, and compare the estimate with current official guidance for 2026/27.
Minutes = word count / words per minuteWorked example
1,500 words at 250 wpm takes about 6 minutes.
number = coefficient x 10^exponentWorked example
123,000 becomes 1.23 x 10^5.
Daily study = remaining hours / available daysWorked example
30 hours across 10 days requires 3 hours per day.
z = (score - mean) / standard deviationWorked example
A score one standard deviation above the mean is around the 84th percentile.
Fuel used = distance x efficiency / 100; CO2 = fuel used x emission factorWorked example
1,000 km at 7 L/100 km uses 70 L fuel.
Liters = roof area sq m x rainfall mm x efficiencyWorked example
100 sq m roof and 50 mm rain at 80% efficiency collects about 4,000 L.
Energy = system kW x sun hours x performance ratio x daysWorked example
A 5 kW system with 5 sun hours and 80% performance makes about 20 kWh per day.
Runtime hours = battery mAh x efficiency / load mAWorked example
5,000 mAh at 500 mA and 85% efficiency lasts about 8.5 hours.
Monthly km = one-way distance x 2 x commute days; fuel = km x efficiency / 100Worked example
20 km each way for 22 days is 880 km per month.
kWh = watts / 1000 x hours per day x days; cost = kWh x rateWorked example
1,000 W used 3 hours daily for 30 days uses 90 kWh.
Heat index estimates apparent temperature from Fahrenheit temperature and relative humidityWorked example
High humidity can make 92 F feel much hotter.
Cubic feet = length x width x average depth; gallons = cubic feet x 7.48052Worked example
A 30 x 15 x 5 ft pool holds about 16,831 gallons.
Total = usage x rate + fixed charge + tax or feesWorked example
12 units at 3.50 plus 15 fixed charge and 5% fees gives the estimate.
Wind chill uses Fahrenheit temperature and wind speed in mphWorked example
30 F with 15 mph wind feels colder than calm 30 F air.
Employee contribution = min(salary x contribution %, 2026 elective limit); employer match = eligible contribution x match %Worked example
At 100,000 salary, 10% contribution, and a 50% match on the first 6%, employee contribution is 10,000 and estimated match is 3,000.
Payment = balance x monthly rate / (1 - (1 + monthly rate)^-months)Worked example
Spread a retirement balance across a selected payout term.
Finance
Australia Capital Gains Tax Calculator calculation method
Australia Capital Gains Tax CalculatorAustralia Capital Gains Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative investing scenario for Australia, review every editable rule, and compare the estimate with current official guidance for 2026/27.
GST = net price x rate; gross price = net price + GST; net price = gross price / (1 + rate)Worked example
At 10% GST, 1,000 before GST has 100 GST and a gross price of 1,100.
Finance
Australia Income Tax and Medicare Levy Calculator calculation method
Australia Income Tax and Medicare Levy CalculatorAustralia Income Tax and Medicare Levy Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for Australia, review every editable rule, and compare the estimate with current official guidance for 2026/27.
Finance
Australia PAYG Withholding Calculator calculation method
Australia PAYG Withholding CalculatorAustralia PAYG Withholding Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for Australia, review every editable rule, and compare the estimate with current official guidance for 2026/27.
Australia Stamp Duty Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative property scenario for Australia, review every editable rule, and compare the estimate with current official guidance for 2026/27.
Finance
Australia Super Guarantee Calculator calculation method
Australia Super Guarantee CalculatorAustralia Super Guarantee Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative retirement scenario for Australia, review every editable rule, and compare the estimate with current official guidance for 2026/27.
Amount financed = price - down payment - trade-in + tax + fees; payment uses the loan amortization formulaWorked example
A 30,000 car with 5,000 down, 2,000 trade-in, 8% tax, and 6.5% APR is financed over the selected term.
Estimated value = troy ounces x metal price per troy ounce x purity factor x market adjustment x currency rateWorked example
One tola is about 11.6638 grams, or 0.375 troy oz. Country retail bases approximate local premiums above international spot, but city and dealer quotes can still differ.
CAGR = (ending value / beginning value)^(1 / years) - 1Worked example
If 10,000 grows to 16,105 over 5 years, CAGR is about 10%.
Canada Capital Gains Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative investing scenario for Canada, review every editable rule, and compare the estimate with current official guidance for 2026.
Total tax = net price x combined rate; gross price = net price + total tax; net price = gross price / (1 + combined rate)Worked example
In Ontario, 1,000 before 13% HST has 130 tax and a gross price of 1,130.
Canada Income Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for Canada, review every editable rule, and compare the estimate with current official guidance for 2026.
Canada Land Transfer Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative property scenario for Canada, review every editable rule, and compare the estimate with current official guidance for 2026.
Finance
Canada Payroll Deductions Calculator calculation method
Canada Payroll Deductions CalculatorCanada Payroll Deductions Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for Canada, review every editable rule, and compare the estimate with current official guidance for 2026.
Finance
Canada RRSP Deduction Limit Calculator calculation method
Canada RRSP Deduction Limit CalculatorCanada RRSP Deduction Limit Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative retirement scenario for Canada, review every editable rule, and compare the estimate with current official guidance for 2026.
Finance
Canada TFSA Contribution Room Calculator calculation method
Canada TFSA Contribution Room CalculatorCanada TFSA Contribution Room Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative savings scenario for Canada, review every editable rule, and compare the estimate with current official guidance for 2026.
Tax due = max(sale proceeds - cost basis, 0) x tax rateWorked example
A 2,000 gain at 15% tax owes about 300 before local rules.
A = P x (1 + r / n)^(n x t)Worked example
10,000 at 8% compounded monthly for 5 years becomes 10,000 x (1 + 0.08 / 12)^60.
Each month: interest = balance x APR / 12; principal paid = payment - interestWorked example
A 5,000 balance at 21% APR with 250 monthly payments takes about 25 months.
Converted amount = amount x exchange rateWorked example
If 1 USD = 0.86 EUR, then 100 USD converts to about 86 EUR.
Converted amount = amount x historical rateWorked example
Enter the rate from your bank statement, broker report, central bank table, or market data source for the date you are researching.
Months are estimated from balance, APR, and monthly paymentWorked example
Avalanche prioritizes highest APR first; snowball prioritizes lowest balance first.
DTI = monthly debt payments / gross monthly incomeWorked example
2,700 total payments on 7,000 gross income is about 38.6% DTI.
Dividend yield = annual dividend per share / share priceWorked example
A 2.40 annual dividend on a 60 share is a 4% yield.
Future value = contribution x (((1 + r)^n - 1) / r)Worked example
Monthly contributions compound using the selected annual return.
EAR = (1 + nominal rate / compounds)^compounds - 1Worked example
8% compounded monthly has an effective annual rate above 8%.
Target = monthly expenses x months; remaining = target - current savingsWorked example
3,000 monthly expenses for 6 months gives an 18,000 target.
Monthly EPF addition = employee EPF + employer EPF; employer EPF = employer contribution - EPS diversionWorked example
At 50,000 monthly basic plus DA and 12% contributions, employee EPF is 6,000/month while part of the employer contribution may be diverted to EPS.
FICA = Social Security tax + Medicare tax + Additional Medicare taxWorked example
For 100,000 of FICA wages, employee Social Security is 6.2% up to the wage base and Medicare is 1.45% of all wages.
Fuel needed = distance x fuel efficiency / 100; trip cost = fuel needed x fuel priceWorked example
A 250 km trip at 7.5 L/100 km uses 18.75 L. At 1.35 per L, the trip costs about 25.31.
Finance
Germany Capital Income Tax Calculator calculation method
Germany Capital Income Tax CalculatorGermany Capital Income Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative investing scenario for Germany, review every editable rule, and compare the estimate with current official guidance for 2026.
Finance
Germany Church Tax and Solidarity Surcharge Calculator calculation method
Germany Church Tax and Solidarity Surcharge CalculatorGermany Church Tax and Solidarity Surcharge Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for Germany, review every editable rule, and compare the estimate with current official guidance for 2026.
Finance
Germany Net Salary and Social Insurance Calculator calculation method
Germany Net Salary and Social Insurance CalculatorGermany Net Salary and Social Insurance Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for Germany, review every editable rule, and compare the estimate with current official guidance for 2026.
Finance
Germany Real Estate Transfer Tax Calculator calculation method
Germany Real Estate Transfer Tax CalculatorGermany Real Estate Transfer Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative property scenario for Germany, review every editable rule, and compare the estimate with current official guidance for 2026.
VAT = net price x rate; gross price = net price + VAT; net price = gross price / (1 + rate)Worked example
At 19% VAT, 1,000 before VAT has 190 VAT and a gross price of 1,190.
Germany Wage Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for Germany, review every editable rule, and compare the estimate with current official guidance for 2026.
HRA exemption = least of actual HRA received, rent paid - 10% of salary, and 40% or 50% of salaryWorked example
If salary is 600,000, HRA is 240,000, rent is 300,000, and city type is metro, exemption is min(240,000, 240,000, 300,000) = 240,000.
India Advance Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for India, review every editable rule, and compare the estimate with current official guidance for FY 2025-26 / AY 2026-27.
India Capital Gains Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for India, review every editable rule, and compare the estimate with current official guidance for FY 2025-26 / AY 2026-27.
GST amount = base amount x GST rate / 100; inclusive base = GST-inclusive amount / (1 + rate / 100)Worked example
At 18% GST, 1,000 before GST has 180 GST and total 1,180. If 1,180 already includes GST, base is 1,000 and GST is 180.
Finance
India House Property Income Calculator calculation method
India House Property Income CalculatorIndia House Property Income Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for India, review every editable rule, and compare the estimate with current official guidance for FY 2025-26 / AY 2026-27.
Taxable income = gross income - standard deduction - eligible old-regime deductions; tax = slab tax - rebate/relief + 4% cessWorked example
For salary income of 1,200,000 in the new regime, standard deduction lowers taxable income to 1,125,000 and the ordinary-income rebate makes slab tax zero.
India Salary TDS Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for India, review every editable rule, and compare the estimate with current official guidance for FY 2025-26 / AY 2026-27.
Finance
India Stamp Duty and Registration Calculator calculation method
India Stamp Duty and Registration CalculatorIndia Stamp Duty and Registration Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative property scenario for India, review every editable rule, and compare the estimate with current official guidance for FY 2025-26 / AY 2026-27.
Future cost = current cost x (1 + inflation rate)^yearsWorked example
At 3% inflation, 1,000 grows to about 1,159 after 5 years.
Remaining allowance = annual ISA allowance - current subscriptions - allowed planned contributionWorked example
If 10,000 has already been subscribed and you plan another 8,000, the remaining adult ISA allowance is 2,000.
Principal is solved from payment, monthly rate, and number of paymentsWorked example
A fixed monthly budget can be converted into an estimated affordable loan amount.
Payment = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1)Worked example
For a 100,000 loan at 7.5% for 5 years, use monthly rate 0.075 / 12 and 60 payments.
Calculate each fixed payment, then compare payment and total interestWorked example
Compare a shorter higher-payment loan with a longer lower-payment loan.
Monthly payment = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1)Worked example
For a 500,000 loan at 8% annual interest for 5 years, use monthly rate r = 8 / 12 / 100 and n = 60 months.
Payment = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1)Worked example
For a 300,000 mortgage at 6.5% for 30 years, n is 360 monthly payments.
Break-even months = points cost / monthly payment savingsWorked example
3,000 points cost and 100 monthly savings breaks even in 30 months.
Break-even months = closing costs / monthly savingsWorked example
4,000 closing costs and 200 monthly savings breaks even in 20 months.
Net worth = total assets - total liabilitiesWorked example
Cash, investments, and property minus loans and card balances.
Finance
New Zealand Bright-Line Property Tax Calculator calculation method
New Zealand Bright-Line Property Tax CalculatorNew Zealand Bright-Line Property Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative property scenario for New Zealand, review every editable rule, and compare the estimate with current official guidance for 2026/27.
GST = net price x rate; gross price = net price + GST; net price = gross price / (1 + rate)Worked example
At 15% GST, 1,000 before GST has 150 GST and a gross price of 1,150.
New Zealand Income Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for New Zealand, review every editable rule, and compare the estimate with current official guidance for 2026/27.
New Zealand KiwiSaver Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative retirement scenario for New Zealand, review every editable rule, and compare the estimate with current official guidance for 2026/27.
New Zealand PAYE Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for New Zealand, review every editable rule, and compare the estimate with current official guidance for 2026/27.
Finance
New Zealand Provisional Tax Calculator calculation method
New Zealand Provisional Tax CalculatorNew Zealand Provisional Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for New Zealand, review every editable rule, and compare the estimate with current official guidance for 2026/27.
Projected corpus grows monthly contributions, then splits final corpus into lump sum and annuity portionsWorked example
If the annuity share is 40%, the calculator puts 40% of the projected corpus into annuity and estimates monthly pension from the annuity rate.
NPV = sum(cash flow in year t / (1 + discount rate)^t) - initial investmentWorked example
Discount future cash flows to today, then subtract the upfront investment.
Finance
Pakistan ATL Filer vs Non-Filer Tax Impact Calculator calculation method
Pakistan ATL Filer vs Non-Filer Tax Impact CalculatorPakistan ATL Filer vs Non-Filer Tax Impact Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for Pakistan, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
Finance
Pakistan Capital Gains Tax Calculator calculation method
Pakistan Capital Gains Tax CalculatorPakistan Capital Gains Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative investing scenario for Pakistan, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
Finance
Pakistan Property Transfer Tax Calculator calculation method
Pakistan Property Transfer Tax CalculatorPakistan Property Transfer Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative property scenario for Pakistan, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
Finance
Pakistan Salary Income Tax Calculator calculation method
Pakistan Salary Income Tax CalculatorPakistan Salary Income Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for Pakistan, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
Sales tax = net price x rate; gross price = net price + sales tax; net price = gross price / (1 + rate)Worked example
At 18% sales tax, 1,000 before tax has 180 sales tax and a gross price of 1,180.
Pakistan Withholding Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for Pakistan, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
Payback period = initial investment / annual cash flowWorked example
A 50,000 investment producing 12,000 per year pays back in about 4.17 years.
Qualifying earnings = capped salary - lower qualifying earnings limit; contributions = qualifying earnings x contribution ratesWorked example
For 35,000 salary, qualifying earnings are 28,760 before applying employee and employer contribution percentages.
Balance is projected yearly: balance = (opening balance + annual deposit) x (1 + annual rate)Worked example
An annual deposit of 150,000 at 7.1% for 15 years is projected year by year with interest credited annually.
PV = FV / (1 + r)^nWorked example
100,000 due in 10 years at 7% has a lower present value today.
FV = P x (((1 + i)^n - 1) / i) x (1 + i)Worked example
For a monthly investment of 5,000 at 12% annual return for 10 years, use i = 12 / 12 / 100 and n = 120 months.
Buy cost = mortgage payment + taxes/insurance/maintenance - rentWorked example
A positive difference means buying costs more per month than renting under the entered assumptions.
FV = current x (1 + r)^n + contribution x (((1 + r)^n - 1) / r)Worked example
Monthly contributions compound with the selected annual return over the chosen years.
Allowed contribution = annual limit reduced across the MAGI phase-out range; projected balance grows yearlyWorked example
For a single filer under age 50, the 2026 limit is 7,500 before income phase-out. MAGI inside the phase-out range reduces the allowed contribution.
Annual salary = hourly rate x hours per week x weeks per yearWorked example
25 per hour x 40 hours x 52 weeks = 52,000 per year.
Monthly saving = remaining goal / monthsWorked example
To save 12,000 in 24 months from 2,000 saved, save about 417 per month.
Interest = Principal x Rate x Time / 100Worked example
10,000 at 8% for 3 years earns 10,000 x 8 x 3 / 100 = 2,400 interest.
Finance
Singapore CPF Contribution Calculator calculation method
Singapore CPF Contribution CalculatorSingapore CPF Contribution Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for Singapore, review every editable rule, and compare the estimate with current official guidance for 2026.
GST = net price x rate; gross price = net price + GST; net price = gross price / (1 + rate)Worked example
At 9% GST, 1,000 before GST has 90 GST and a gross price of 1,090.
Singapore Income Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for Singapore, review every editable rule, and compare the estimate with current official guidance for 2026.
Finance
Singapore Property Stamp Duty Calculator calculation method
Singapore Property Stamp Duty CalculatorSingapore Property Stamp Duty Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative property scenario for Singapore, review every editable rule, and compare the estimate with current official guidance for 2026.
Singapore Property Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative property scenario for Singapore, review every editable rule, and compare the estimate with current official guidance for 2026.
Finance
Singapore Self-Employed MediSave Calculator calculation method
Singapore Self-Employed MediSave CalculatorSingapore Self-Employed MediSave Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for Singapore, review every editable rule, and compare the estimate with current official guidance for 2026.
Tax amount = base x rate / 100; pre-tax amount = inclusive amount / (1 + rate / 100)Worked example
At 18% tax, 1,000 before tax has 180 tax and total 1,180.
Tip = bill x tip rate; per person = (bill + tip) / peopleWorked example
An 80 bill with an 18% tip is 94.40 total. Split four ways, each person pays 23.60.
UAE Corporate Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for UAE, review every editable rule, and compare the estimate with current official guidance for 2026.
Finance
UAE End of Service Gratuity Calculator calculation method
UAE End of Service Gratuity CalculatorUAE End of Service Gratuity Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for UAE, review every editable rule, and compare the estimate with current official guidance for 2026.
UAE Excise Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for UAE, review every editable rule, and compare the estimate with current official guidance for 2026.
VAT = net price x rate; gross price = net price + VAT; net price = gross price / (1 + rate)Worked example
At 5% VAT, 1,000 before VAT has 50 VAT and a gross price of 1,050.
UK Capital Gains Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for United Kingdom, review every editable rule, and compare the estimate with current official guidance for Tax year 2026/27.
UK Dividend Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for United Kingdom, review every editable rule, and compare the estimate with current official guidance for Tax year 2026/27.
Take-home pay = gross employment income - pre-tax deductions - income tax - employee National InsuranceWorked example
For 60,000 employment income in England, Wales, or Northern Ireland, the estimate applies the Personal Allowance, tax bands, and employee NI bands.
UK Savings Interest Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for United Kingdom, review every editable rule, and compare the estimate with current official guidance for Tax year 2026/27.
Finance
UK Self Assessment Payments on Account Calculator calculation method
UK Self Assessment Payments on Account CalculatorUK Self Assessment Payments on Account Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for United Kingdom, review every editable rule, and compare the estimate with current official guidance for Tax year 2026/27.
SDLT = sum of each property price slice x marginal SDLT rateWorked example
A 295,000 standard residential purchase pays 0% on the first 125,000, 2% on the next 125,000, and 5% on the remaining 45,000.
Finance
UK Student Loan Repayment Calculator calculation method
UK Student Loan Repayment CalculatorUK Student Loan Repayment Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for United Kingdom, review every editable rule, and compare the estimate with current official guidance for Tax year 2026/27.
VAT = net price x rate; gross price = net price + VAT; net price = gross price / (1 + rate)Worked example
At 20% VAT, 1,000 before VAT has 200 VAT and a gross price of 1,200.
US Capital Gains Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative investing scenario for United States, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
Finance
US Child Tax Credit and EITC Estimator calculation method
US Child Tax Credit and EITC EstimatorUS Child Tax Credit and EITC Estimator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for United States, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
Finance
US Estimated Quarterly Tax Calculator calculation method
US Estimated Quarterly Tax CalculatorUS Estimated Quarterly Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for United States, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
Taxable income = gross income - deduction; federal tax = bracket tax - tax creditsWorked example
For a single filer with 95,000 gross income and the 2026 standard deduction, taxable income is 79,250 and ordinary bracket tax is estimated from the 2026 IRS brackets.
US Paycheck Withholding Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative payroll scenario for United States, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
US Self-Employment Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for United States, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
US State Income Tax Calculator estimate = applicable base amounts adjusted by the entered rates, thresholds, allowances, credits, caps, and prior paymentsWorked example
Enter a representative tax scenario for United States, review every editable rule, and compare the estimate with current official guidance for Tax year 2026.
Total caffeine = drinks x caffeine per drinkWorked example
3 coffees at 95 mg each gives 285 mg caffeine.
Area = pi x (diameter / 2)^2; unit price = price / areaWorked example
A 16 inch pizza often has much more area than a 12 inch pizza.
Total cost = sum ingredient costs; cost per serving = total / servingsWorked example
A 24 recipe split into 6 servings costs 4 per serving.
Per serving = recipe total / servingsWorked example
1,800 calories across 6 servings gives 300 calories per serving.
Planet age = Earth age / planet orbital period in Earth yearsWorked example
30 Earth years is about 15.95 Mars years.
P(match) = 1 - product((365 - i) / 365)Worked example
A group of 23 people has about a 50% chance of a shared birthday.
Probability = nCk / 2^nWorked example
Exactly 5 heads in 10 flips has probability 10C5 / 1024.
Probability = favorable outcomes / total outcomesWorked example
With two six-sided dice, rolling a total of 7 has 6 favorable outcomes out of 36.
First year = 15 human years, second year = 9 more, later years vary by sizeWorked example
A 5-year medium dog is roughly 45 human years.
Category is based on systolic and diastolic thresholdsWorked example
120/80 can fall into an elevated or stage category depending on guidelines.
BMI = weight in kg / (height in meters)^2Worked example
A person weighing 70 kg and 1.75 m tall has BMI = 70 / 1.75^2 = 22.86.
BMI prime = BMI / 25Worked example
BMI 27.5 gives BMI prime 1.10.
Men: 10w + 6.25h - 5a + 5; Women: 10w + 6.25h - 5a - 161Worked example
A 30-year-old man at 80 kg and 180 cm has BMR = 10x80 + 6.25x180 - 5x30 + 5 = 1,780.
Body fat % = 1.20 x BMI + 0.23 x age - 10.8 x sex - 5.4Worked example
Sex is 1 for male and 0 for female in this common adult estimate.
BSA = sqrt(height(cm) x weight(kg) / 3600)Worked example
A person who is 170 cm and 70 kg has BSA = sqrt(170 x 70 / 3600), about 1.82 sq m.
BMR = 10w + 6.25h - 5a + s; TDEE = BMR x activity factorWorked example
For men s = 5, for women s = -161. Multiply BMR by activity level for daily calories.
Daily deficit = maintenance + exercise - intakeWorked example
2,400 maintenance + 200 exercise - 1,900 intake gives a 700 kcal deficit.
Men: 50 + 2.3 x inches over 5 ft; Women: 45.5 + 2.3 x inches over 5 ftWorked example
A 5 ft 10 in adult male estimate is 50 + 2.3 x 10 = 73 kg.
Male LBM = 0.407W + 0.267H - 19.2; Female LBM = 0.252W + 0.473H - 48.3Worked example
The formula uses weight in kg and height in cm.
Protein and carbs use 4 kcal/g; fat uses 9 kcal/gWorked example
2,000 kcal at 30% protein equals 150 g protein.
1RM = weight x (1 + reps / 30)Worked example
100 kg for 5 reps estimates a 1RM of about 117 kg.
Ovulation date = next period date - 14 daysWorked example
For a 28-day cycle, ovulation is estimated around day 14.
Estimated due date = LMP + 280 daysWorked example
A last menstrual period on 1 January gives an estimated due date around 8 October.
Daily protein = body weight kg x grams per kgWorked example
70 kg at 1.6 g/kg gives 112 g protein per day.
Pace = total time / distance; speed = distance / timeWorked example
A 5 km run in 25 minutes is 5:00 per km, about 8:03 per mile, and 12 km/h.
Bedtime = wake time - sleep cycles x 90 minutesWorked example
For 5 cycles before 7:00 AM, bedtime is about 11:30 PM.
Max HR = 220 - age; zones are percentages of max HRWorked example
Moderate is often 50-70% of estimated max heart rate.
VO2 max = 15.3 x max heart rate / resting heart rateWorked example
Max HR 190 and resting HR 60 gives about 48.5 ml/kg/min.
WHR = waist circumference / hip circumferenceWorked example
A 32 inch waist and 40 inch hip gives a ratio of 0.80.
Daily water = body weight x 35 ml, adjusted for activityWorked example
70 kg x 35 ml = 2,450 ml before activity adjustment.
a_n = a_1 + (n - 1)d; sum = n(a_1 + a_n)/2Worked example
First term 3, difference 4, term 10 gives 39.
Average = sum of values / number of valuesWorked example
The average of 10, 20, and 30 is 60 / 3 = 20.
Area = pi r^2; circumference = 2 pi r; diameter = 2rWorked example
A radius of 5 gives area about 78.54.
Volume = pi r^2 h; surface area = 2 pi r(r + h)Worked example
Radius 3 and height 10 gives volume about 282.74.
d = sqrt((x2 - x1)^2 + (y2 - y1)^2)Worked example
The distance from (1,2) to (7,10) is 10.
Power = base^exponentWorked example
2^10 equals 1,024.
n! = n x (n - 1) x ... x 1Worked example
8! equals 40,320.
a/b + c/d = (ad + bc) / bdWorked example
1/2 + 1/3 = (1x3 + 1x2) / 6 = 5/6.
LCM(a,b) = abs(a x b) / GCD(a,b)Worked example
GCD of 12 and 18 is 6; LCM is 36.
a_n = a_1 r^(n - 1); sum = a_1(1 - r^n)/(1 - r)Worked example
First term 3, ratio 2, term 8 gives 384.
log_b(x) = ln(x) / ln(b)Worked example
log base 10 of 1,000 equals 3.
Midpoint = ((x1 + x2) / 2, (y1 + y2) / 2)Worked example
The midpoint of (1,2) and (7,10) is (4,6).
Decimal values are represented in base 2, base 8, and base 16Worked example
Decimal 255 is binary 11111111 and hex FF.
Percent of number = number x percent / 100; change % = (new - old) / old x 100Worked example
15% of 240 is 240 x 15 / 100 = 36. A change from 80 to 100 is 25%.
Change % = (new value - old value) / old value x 100Worked example
A move from 80 to 100 is a 25% increase.
nPr = n! / (n - r)!; nCr = n! / (r! x (n - r)!)Worked example
Choosing 3 from 10 gives 720 permutations and 120 combinations.
A prime number has exactly two positive divisors: 1 and itselfWorked example
29 is prime; 30 is not prime.
c = sqrt(a^2 + b^2)Worked example
Legs 3 and 4 give hypotenuse 5.
x = (-b +/- sqrt(b^2 - 4ac)) / 2aWorked example
x^2 - 3x + 2 has roots 1 and 2.
Simplified ratio = A / gcd(A, B) : B / gcd(A, B)Worked example
The ratio 12:18 simplifies to 2:3.
Volume = length x width x height; surface area = 2(lw + lh + wh)Worked example
6 by 4 by 3 gives volume 72.
Use descending symbols M, CM, D, CD, C, XC, L, XL, X, IX, V, IV, IWorked example
1994 converts to MCMXCIV.
Supports sin, cos, tan, inverse trig, ln, log10, sqrt, powers, factorials, pi, e, and parenthesesWorked example
In DEG mode, sin(30) + sqrt(144) evaluates to 12.5.
slope = (y2 - y1) / (x2 - x1)Worked example
Points (1,2) and (5,10) have slope 2.
Volume = 4/3 pi r^3; surface area = 4 pi r^2Worked example
Radius 4 gives volume about 268.08.
Square root of x is the number y where y x y = xWorked example
The square root of 144 is 12 because 12 x 12 = 144.
Mean = sum / count; SD = sqrt(mean squared deviation)Worked example
For 4, 7, 7, 9, 12 the mode is 7.
Area = sqrt(s x (s - a) x (s - b) x (s - c)), where s = perimeter / 2Worked example
A 3-4-5 triangle has area 6 and perimeter 12.
Required bandwidth = users x Mbps per user x (1 + overhead)Worked example
25 users at 5 Mbps each with 20% overhead needs about 150 Mbps.
Monthly transfer = users x sessions x data per sessionWorked example
10,000 users with 4 sessions and 5 MB per session transfer about 200 GB.
Time seconds = file size in megabits / speed MbpsWorked example
A 1 GB file at 100 Mbps takes about 80 seconds before overhead.
Total wait = latency per round trip x number of round tripsWorked example
80 ms latency across 40 round trips adds 3.2 seconds of waiting.
Addresses = 2^(32 - prefix); network = IP AND subnet mask; broadcast = network + addresses - 1Worked example
192.168.1.10/24 belongs to network 192.168.1.0/24 with usable range 192.168.1.1 to 192.168.1.254.
Acceleration = (final velocity - initial velocity) / timeWorked example
0 to 27.8 m/s in 8 seconds gives about 3.48 m/s2.
Density = mass / volumeWorked example
12 kg in 3 cubic meters has density 4 kg/m3.
Force = mass x accelerationWorked example
10 kg at 9.8 m/s2 produces 98 newtons of force.
KE = 0.5 x mass x velocity^2Worked example
80 kg moving at 20 m/s has 16,000 joules of kinetic energy.
Momentum = mass x velocityWorked example
80 kg at 10 m/s has momentum 800 kg m/s.
Resistance = voltage / current; power = voltage x currentWorked example
12 V and 2 A gives 6 ohms and 24 W.
Pressure = force / areaWorked example
500 N over 2 m2 equals 250 Pa.
Range = v^2 sin(2theta) / g; max height = v^2 sin^2(theta) / 2gWorked example
30 m/s at 45 degrees gives the longest ideal range for level ground.
Speed = distance / timeWorked example
100 km in 2.5 hours gives an average speed of 40 km/h; 100 miles in 2.5 hours gives 40 mph.
Torque = force x lever arm x sin(angle)Worked example
100 N at 0.5 m and 90 degrees gives 50 N m.
Wave speed = frequency x wavelengthWorked example
440 Hz and 0.78 m gives about 343 m/s.
Work = force x distance x cos(angle); power = work / timeWorked example
120 N over 10 m at 0 degrees gives 1,200 J.
Calories = MET x 3.5 x weight kg / 200 x minutesWorked example
45 minutes at 8 MET for 70 kg burns about 441 calories.
Predicted time = current time x (target distance / current distance)^1.06Worked example
A 25 minute 5K predicts roughly 52 minutes for 10K.
Distance = steps x stride lengthWorked example
10,000 steps with a 0.75 m stride is about 7.5 km.
P(X = k) = nCk p^k (1 - p)^(n-k)Worked example
10 trials, 3 successes, and 40% success probability can be evaluated exactly.
chi-square = sum((observed - expected)^2 / expected)Worked example
Compare observed category counts with expected counts.
Margin = z x standard deviation / sqrt(sample size)Worked example
Mean 50, SD 10, n 100, and 95% confidence gives margin 1.96.
r = sum((x - mean x)(y - mean y)) / sqrt(sum(x - mean x)^2 sum(y - mean y)^2)Worked example
Five x-y pairs can show positive, negative, or weak linear association.
P(X = k) = e^-lambda x lambda^k / k!Worked example
Average rate 4 and exactly 2 events gives a Poisson probability.
P(A and B) = P(A) x P(B); P(A or B) = P(A) + P(B) - P(A and B)Worked example
If A is 40% and B is 30%, both happen with 12% probability.
n = z^2 x p x (1 - p) / e^2Worked example
95% confidence, 5% margin, and 50% proportion needs about 385 responses.
SE = standard deviation / sqrt(sample size)Worked example
SD 12 and n 64 gives standard error 1.5.
Weighted average = sum(value x weight) / sum(weights)Worked example
Scores weighted 40, 35, and 25 percent combine into one weighted score.
z = (value - mean) / standard deviationWorked example
A value of 85 with mean 70 and SD 10 has z = 1.5.
Driving hours = distance / average speed; total time = driving time + stop timeWorked example
300 km at 75 km/h takes 4 hours before breaks.
L/100 km = fuel liters / distance km x 100Worked example
35 L over 500 km gives 7 L/100 km.
Range = usable fuel / efficiency x 100Worked example
A 50 L tank at 60% with 5 L reserve and 7 L/100 km gives about 357 km usable range.
Total = lodging + food + transport + activities + contingencyWorked example
Four days, two travelers, 120/night lodging, 45/day food, 200 transport, and 160 activities gives a compact trip budget.
UK size is about US + 4; EU size is about US + 30Worked example
US 8 is roughly UK 12 and EU 38.
Scaled amount = original amount x target servings / original servingsWorked example
2 cups for 4 servings becomes 3 cups for 6 servings.
EU is estimated from selected US size; UK is about US - 1 for men and US - 2 for womenWorked example
US men's 9 is roughly UK 8 and EU 42.
How to read the notation
Symbols are defined by each formula and example. Common conventions include P for principal, r for a rate per period, n for a count of periods, and t for time. Rates may need conversion from a percentage to a decimal.
Rounding and precision
Keep full precision during intermediate steps and round only the displayed result unless a regulation specifies another method. Currency, payroll, tax, and measurement standards can require different rounding rules.
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Editorial method
How formulas enter the library
Each entry comes from a working calculator and includes the formula name, expression, example, and calculator-specific caution.
Where a method depends on an official rate, threshold, regulatory rule, or published scientific relationship, the entry exposes the calculator’s source profile and verification date.
The downloadable dataset uses stable calculator slugs and URLs so publishers can update links without reconstructing Calxo’s internal catalog.
Cite this library
Stable citation and open data formats
Use the citation below for the collection. When referring to one formula, also link to its calculator page so readers can inspect inputs, assumptions, sources, and the live result.
Calxo AI Editorial Team. “Calculator Formula Library.” Version 2026.06.23, updated June 23, 2026. https://www.calxo.ai/formula-library