Date & Time calculator
Age Calculator by Date of Birth
Calculate age in years, months, and days from a date of birth.
FormulaAge = comparison date - date of birth, adjusted by calendar months and days
Formula
Age calculation
Age = comparison date - date of birth, adjusted by calendar months and days
If birth date is 20 May 2000 and comparison date is 20 May 2026, the age is exactly 26 years.
FAQ6 common questions for this calculator.
FAQs
Does the age calculator include months and days?+
Yes. It shows a calendar-aware breakdown in years, months, and days.
Can I calculate age for a past date?+
Yes. Change the comparison date to calculate age on any selected date.
How does the Age Calculator calculate the result?+
For the Age Calculator, it uses the Age calculation: Age = comparison date - date of birth, adjusted by calendar months and days. If birth date is 20 May 2000 and comparison date is 20 May 2026, the age is exactly 26 years.
What information do I need to use the Age Calculator?+
Enter the birth date and the date you want to calculate age on. Use the exact calendar dates because leap years and month lengths affect the result.
How accurate is the Age Calculator?+
Age Calculator is accurate for the values and assumptions entered on this page. It uses the Age calculation. Recheck the inputs before relying on the estimate.
What should I check before using the Age Calculator result?+
For the Age Calculator, check a date of birth, date format, timezone, daylight-saving changes, inclusive or exclusive endpoints, and whether weekends or holidays should count.
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Date & Time guide
How to use the Age Calculator
Calculate age in years, months, and days from a date of birth. The page also explains the age calculation and shows a practical example: If birth date is 20 May 2000 and comparison date is 20 May 2026, the age is exactly 26 years.
- 1
Enter your details
Enter a date of birth, then complete any other fields shown in the calculator.
- 2
Check the calculation
Review the result alongside the age calculation: Age = comparison date - date of birth, adjusted by calendar months and days.
- 3
Compare scenarios
Change one or more inputs to see how they affect the age Calculator result before you use the estimate.