Calxo AI widget
BMI Calculator
Calculate adult BMI from height and weight, then use age and sex for an estimated body-fat percentage and contextual guidance.
Powered by Calxo AI
Calxo AI widget
Calculate adult BMI from height and weight, then use age and sex for an estimated body-fat percentage and contextual guidance.
Powered by Calxo AI
Used by the body-fat equation; it does not change adult BMI.
BMI
23.5
Adult category
Normal
Estimated body fat
18.9%
BMI healthy-weight range
56.7-76.3 kg
For adults age 20+, categories use the BMI score regardless of age or sex.
23.5
Working
BMI compares weight with height squared, then maps the score to a broad screening category.
BMI = 23.5 (Normal)
Step 1Prepare height
175 cm = 1.75 m
BMI uses height in meters for metric inputs or total inches for imperial inputs.
Step 2Apply BMI formula
72 / (1.75 x 1.75) = 23.5
Step 3Read category
23.5 -> Normal
Adult categories apply from age 20 and are not changed by age or sex.
Step 4Estimate body fat
1.2 x 23.5 + 0.23 x 30 - 10.8 x 1 - 5.4 = 18.9%
This companion estimate uses adult BMI, age, and the selected sex constant.
Further explanation
Height is squared because BMI compares weight against body size, not height alone.
Age and sex add context through the body-fat estimate; they do not alter adult BMI categories.
Children and teens require age- and sex-specific BMI percentiles rather than adult thresholds.
How to use
Need a tape-measure estimate? Use the Body Fat Calculator.
Input terms
Output terms
Previous results will appear here after you use another calculator.