Health calculator
Body Fat Percentage Calculator
Estimate body fat percentage from BMI, age, and sex.
Formula
BMI-based estimate
This is a rough estimate and can differ from clinical, DEXA, or caliper measurements.
Body fat % = 1.20 x BMI + 0.23 x age - 10.8 x sex - 5.4
Sex is 1 for male and 0 for female in this common adult estimate.
Sources and assumptions
Source notes
This calculator includes source notes, assumptions, and exclusions so the result is easier to verify before use.
- Effective year
- Current rules
- Last verified
- 2026-06-18
This is a rough estimate and can differ from clinical, DEXA, or caliper measurements.
Official and reference sources
Assumptions
Not included
FAQs
Is this body fat result exact?+
No. It is an estimate and can differ from clinical or caliper measurements.
How does the Body Fat Percentage Calculator calculate the result?+
It uses the BMI-based estimate: Body fat % = 1.20 x BMI + 0.23 x age - 10.8 x sex - 5.4. Sex is 1 for male and 0 for female in this common adult estimate.
What information do I need to use the Body Fat Percentage Calculator?+
Estimate body fat percentage from BMI, age, and sex.
How accurate is the Body Fat Percentage Calculator?+
Body Fat Percentage Calculator applies the formula and assumptions shown on this page. Results may be rounded for readability, so verify changing rates, thresholds, medical guidance, or legal rules with the cited source or a qualified professional.
What should I check before using the Body Fat Percentage Calculator result?+
Check that the units, dates, rates, and assumptions match your situation. Change one input at a time to understand which values have the largest effect on the result.
Health guide
How to use the Body Fat Percentage Calculator
Estimate body fat percentage from BMI, age, and sex. The page also explains the BMI-based estimate and shows a practical example: Sex is 1 for male and 0 for female in this common adult estimate.
- 1
Enter your details
Enter bMI, age, and sex, then complete any other fields shown in the calculator.
- 2
Check the calculation
Review the result alongside the BMI-based estimate: Body fat % = 1.20 x BMI + 0.23 x age - 10.8 x sex - 5.4.
- 3
Compare scenarios
Change one or more inputs to see how they affect the body Fat Percentage Calculator result before you use the estimate.
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