Body Fat Calculator
Last updated: 2026-06-25
This calculator estimates your body fat percentage by putting your tape-measure neck and waist (and hip for women) plus height into the U.S. Navy formula.
A typical "healthy" range is about 10–20% for men and 18–28% for women (the chart below uses the 5-step ACE/ACSM breakdown). The result is a reference estimate — for accuracy, use a body composition scale or DEXA.
Estimate body fat from measurements (U.S. Navy method)
Your body fat (U.S. Navy estimate)
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Category: –
- Estimated fat mass
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- Estimated lean mass (muscle, bone, etc.)
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Please enter valid height and neck/waist (and hip for women) measurements.
This result is a tape-measure-based reference estimate. For accurate body composition, use a professional body composition scale or DEXA scan and consult a healthcare provider.
How to use it
- Enter sex and height — select your sex and enter your height in centimeters (cm).
- Enter measurements — use a tape measure for neck and waist (and hip for women), in cm.
- View result — press Calculate to see your body fat percentage, category, and estimated fat and lean mass.
What is the U.S. Navy body fat method?
The U.S. Navy body fat method is a girth-based estimation formula used by the U.S. Navy for physical readiness. Because it needs only a tape measure — no calipers or impedance device — it is the most popular at-home method. It puts your girths and height into a log function to estimate body fat percentage.
U.S. Navy body fat formula (cm)
Men BF% = 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450
Women BF% = 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450
Body fat category chart
| Category | Men | Women |
|---|---|---|
| Essential fat | 2 – 5% | 10 – 13% |
| Athletes | 6 – 13% | 14 – 20% |
| Fitness | 14 – 17% | 21 – 24% |
| Average | 18 – 24% | 25 – 31% |
| Obese | 25% and above | 32% and above |
The chart above is the 5-step ACE/ACSM breakdown, and this calculator's category follows it. The "healthy range (10–20% men, 18–28% women)" mentioned in the TL;DR and FAQ is a broader general "normal" band, so it can look different from the detailed steps in the chart.
Measuring tips
- Measure the neck just below the larynx; the waist at the navel (men) or narrowest point (women).
- Keep the tape against the skin without compressing it, and measure while exhaling.
- As a girth-based estimate, it can be off by about ±3–4% versus impedance scales or DEXA.
- It's more useful to track the trend with the same method than to chase an absolute number.
To also check weight and BMI, try the BMI Calculator and Ideal Weight Calculator.
Frequently asked questions (FAQ)
How does the U.S. Navy body fat method work?
The U.S. Navy method estimates body fat from tape-measure girths and height. For men it uses waist minus neck; for women it uses waist plus hip minus neck, together with height, in a log10 formula. It needs only a tape measure — no calipers or devices — which is why it's so popular.
What is a healthy body fat percentage?
Broadly, 10–20% for men and 18–28% for women is considered a healthy range. Men above 25% and women above 32% are classified as obese. Athletes are lower, and you should not drop below essential fat (2–5% men, 10–13% women).
Where and how do I measure?
Measure the neck just below the larynx, the waist at the navel for men or the narrowest point for women, and the hip (women) at the widest point. Exhale, and keep the tape against the skin without compressing it.
How does this compare to a body composition scale or DEXA?
The Navy method estimates from girths only, so it is less precise than bioelectrical impedance scales or DEXA (about ±3–4%). It's well suited to tracking trends with the same method over time. Use professional equipment for accurate measurement.
Can I use this number for medical decisions?
No. This result is a reference estimate. For an accurate diagnosis and management of obesity or health status, rely on professional body composition analysis and a healthcare provider.
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Last updated: 2026-06-25