Body fat calculator
Calculator
The calculator needs JavaScript. The tables below give the same numbers for common cases.
How it is worked out
- The method uses height and circumferences measured in cm: %BF = 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450.
- It is an estimate with a margin of several percentage points; a medical test is more accurate.
| Inputs | Answer |
|---|---|
| Sex: Male; Height: 178; Neck circumference: 38; Waist circumference: 85; Hip circumference: 95 | The U.S. Navy method estimates your body fat at about 16.4%. |
| Sex: Female; Height: 165; Neck circumference: 32; Waist circumference: 75; Hip circumference: 98 | The U.S. Navy method estimates your body fat at about 28.9%. |
| Sex: Male; Height: 185; Neck circumference: 40; Waist circumference: 95; Hip circumference: 100 | The U.S. Navy method estimates your body fat at about 21.1%. |
How to use it
The U.S. Navy method estimates body fat from circumferences. For men it uses height, neck and waist; for women height, neck, waist and hip. The formula uses base-10 logarithms of the measurements in centimetres.
It is an estimate with a margin of several percentage points. Measure the waist at the navel, relaxed, and the neck below the larynx. Methods such as DEXA scans are more accurate. This is general information and an estimate, not medical advice; talk to a healthcare professional about your own situation.
Frequently asked questions
How accurate is the Navy body fat method?
It can be off by several percentage points; use it to track change over time with the same technique.
Where do I measure my waist?
At the navel for men, and at the narrowest point or navel for women, relaxed and not pulled tight.
What is a healthy body fat percentage?
It varies by age and sex; ask a professional rather than relying on a single number.
Method: standard arithmetic shown step by step; no outside data is used. Checked 2026-11-12.
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General information only. Results are plain arithmetic on the numbers you enter; check anything important (money, health, school work) against your own records or the official source.