Body Fat Calculator
The Body Fat Calculator estimates your body fat percentage using measurements and the US Navy formula. A more accurate estimate than BMI for assessing body composition.
Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.
Body Fat Calculator
Calculate Body Fat Percentage
📐 Formula & Method
US Navy Formula (Men)
For men, using waist and neck circumferences.
US Navy Formula (Women)
For women, using waist, hip, and neck circumferences.
📋 How to Use
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1
Select your gender.
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2
Enter your height in centimeters.
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3
Measure and enter your waist circumference at the narrowest point.
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4
Measure and enter your neck circumference just below the larynx.
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5
Women: also enter hip circumference at the widest point.
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6
Click "Calculate".
Understanding Body Fat Percentage
Body fat percentage is the total mass of fat divided by total body mass. Essential fat is necessary for normal physiological functions. Athletes typically have 6–13% (men) or 14–20% (women) body fat. Fitness ranges are 14–17% and 21–24% respectively.
🔬 Methodology & Accuracy
Formula: Uses the standard mathematical formula shown in the Formula & Method section above. All computations run client-side in your browser — no data is sent to our servers.
Data sources: Tax bands, contribution limits and regulatory rates are taken from official US (IRS, SSA) and UK (HMRC, gov.uk) publications for the current tax year, and updated when bands change.
Last reviewed: June 2026 · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.
For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.