What is the Body Fat Calculator?
The body fat calculator estimates your body fat percentage with the US Navy method, which needs only a tape measure. It is a practical way to track progress without special equipment.
How to use the Body Fat tool
- Enter Sex, Height, Neck and Waist.
- The result updates instantly as you type, or press Calculate.
- Use Try an example to see how it works, and Reset to start again.
Formula
US Navy (men): 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450. Women also use the hip measurement.
Worked example
With sex Male, height 175 cm, neck 38 cm, waist 85 cm, hip (women only) 95 cm, the body fat comes to 16.9%.
Frequently asked questions
How do I measure correctly?
Measure the neck below the larynx, and the waist at the navel for men or the narrowest point for women. Keep the tape level and snug.
What is a healthy body fat percentage?
Roughly 10 to 20% for men and 18 to 28% for women, varying with age and fitness.
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Checked by Calcovate · Formula tested against worked examples · Updated 7 Nov 2026 · How we check our calculators. General information only, not financial or medical advice.