Body Fat Percentage Calculator
Calculate body fat percentage using the US Navy circumference method. Enter waist, neck, height, and hip measurements. Health data never leaves your device — every calculation runs locally in your browser.
How to Use the Body Fat Percentage Calculator
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Frequently Asked Questions
How does the Navy method work?
It uses circumference measurements (waist, neck, hips) and height to estimate body fat percentage using formulas developed by the US Navy. It's a reliable non-caliper method. Worked example — the Fit Male preset (175 cm, waist 80 cm, neck 40 cm) computes 495 ÷ (1.0324 − 0.19077 × log10(40) + 0.15456 × log10(175)) − 450 ≈ 11.1%, which lands in the Athletes band.
What measurements do I need?
For men: waist and neck circumference. For women: waist, neck, and hip circumference. All measurements should be taken at the narrowest point.
How accurate is this method?
Estimates typically land within a few points of DEXA results for average builds — useful for general fitness tracking, not for clinical diagnosis.
What are the body fat categories?
Essential fat (2-5% men, 10-13% women), athletes (6-13% men, 14-20% women), fitness (14-17% men, 21-24% women), acceptable (18-24% men, 25-31% women), obese (25%+ men, 32%+ women). The tool applies these band edges directly: under 6/14/18/25 for men and under 14/21/25/32 for women.
Is my measurement data stored?
No. All calculations run locally in your browser. No body measurements are transmitted.
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Last updated October 2026