Body Fat Percentage Estimator
Estimate your body fat percentage using the US Navy method based on height, neck, waist, and hip measurements.
Measure just below the larynx
Males: at navel | Females: narrowest point
Females only — widest point of hips
How to Use This Calculator
1. Select your sex — the formula differs for males and females 2. Measure your height in cm 3. Measure your neck — circumference just below the larynx 4. Measure your waist — males at the navel, females at the narrowest point 5. Females: measure your hips — at the widest point 6. Enter your weight for fat and lean mass estimates
Measurement Tips:
Formula
US Navy Method — Male: 495/(1.0324 − 0.19077×log(waist−neck) + 0.15456×log(height)) − 450Frequently Asked Questions
How accurate is this method?
The US Navy method has a margin of error of ±3–4% compared to DEXA scans. It's less accurate than hydrostatic weighing or DEXA but far more accessible and still useful for tracking trends.
What is a healthy body fat percentage?
For men: 10–20% is fit to average. For women: 18–28% is fit to average. Athletes are typically lower. Essential fat (minimum for survival) is ~3% for men and ~12% for women.
Why does my waist need to be larger than my neck?
The US Navy formula uses the difference between waist and neck measurements. If they're equal or neck is larger, the logarithm calculation produces an invalid result.
How often should I measure?
Monthly is sufficient. Body fat changes slowly — weekly measurements are prone to fluctuations from water retention, digestion, and measurement error.
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