Health & FitnessReviewed Methodology
Body Fat Calculator
This body fat calculator estimates body fat percentage using BMI, age, and sex inputs.
Quick answer
Body fat is estimated from BMI, age, and sex.
What this tells you
- •Body fat is estimated from BMI, age, and sex.
- •This method gives a practical estimate, not a direct measurement.
- •Use results as guidance and combine with real-world tracking.
How to Use
- 1Enter your weight in kilograms.
- 2Enter your height in centimeters.
- 3Enter your age and sex.
- 4Calculate to estimate body fat percentage.
How It Works
Formula
Body Fat % = 1.20 x BMI + 0.23 x Age - 10.8 x Sex - 5.4 (Sex: 1 male, 0 female)The formula estimates body fat from BMI plus age and sex adjustments.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Adult male estimate
Weight70 kg
Height175 cm
Age30
SexMale
ResultEstimated body fat: 18.7%
Common mistakes
- Entering pounds as kilograms
- Treating estimate as a clinical diagnosis
- Comparing formula estimate directly with device-specific measurements
Limitations
Formula estimates can differ from direct methods such as DEXA or caliper-based assessments.
Frequently Asked Questions
No, it is a formula-based estimate.
The formula includes age as a factor in population-level body composition trends.
Yes, as a consistent estimate over time, alongside other health indicators.