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About the body fat calculator
Body fat percentage says more about your shape than weight alone. This calculator uses the US Navy method, which needs only a tape measure. It uses your height, your neck and your waist — and your hips if you are a woman.
You get your estimated body fat, your category (essential, athletes, fitness, average or above average) and, if you type your weight under More options, your fat mass and lean mass.
How to use it
- Choose kg, cm or lb, ft, in, and your sex
- Type your height
- Measure your neck just below the larynx (Adam's apple), with the tape sloping a little down at the front
- Measure your waist — men at the navel, women at the narrowest part
- Women: measure the hips at the widest part
- Read your body fat in the result. Open More options to add your weight
For the best result, measure in the morning, relaxed, without pulling the tape tight. Take each measurement twice and use the average.
Categories
| Category | Women | Men |
|---|---|---|
| Essential fat | 10–13 % | 2–5 % |
| Athletes | 14–20 % | 6–13 % |
| Fitness | 21–24 % | 14–17 % |
| Average | 25–31 % | 18–24 % |
| Above average | 32 % and more | 25 % and more |
Examples
- A man 70 in (178 cm) tall with a 15 in (38 cm) neck and a 34 in (86 cm) waist has about 17.5 % body fat. That is "fitness".
- A woman 65 in (165 cm) tall with a 13 in (33 cm) neck, a 30 in (76 cm) waist and 38 in (97 cm) hips has about 28.6 %. That is "average".
The formulas
For measurements in inches:
- Men: 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76
- Women: 163.205 × log₁₀(waist + hips − neck) − 97.684 × log₁₀(height) − 78.387
The calculator converts centimetres to inches for you.
How exact is it?
The US Navy method is usually within 3 to 4 percentage points of a lab test. It is good for tracking change over weeks: measure the same way every time. It is not right for very muscular people or for pregnant women.
Frequently asked questions
What is a good body fat percentage?
For health, about 14–24 % for men and 21–31 % for women is a typical range. Athletes are lower. Very low numbers are not healthy.
How can I measure body fat at home?
With a tape measure (this tool), skinfold calipers, or a smart scale. Each has some error, so watch the trend.
Why do women have more body fat?
Women need more essential fat for hormones and childbearing, so their healthy ranges are higher.
Is body fat better than BMI?
BMI cannot tell muscle from fat. Body fat percentage shows more — but it is only an estimate. Use both.
Can I use it when pregnant?
No. The method is not made for pregnancy.
Is this medical advice?
No. It is a general guide. Ask a doctor about your own health.
Good to know
- Your numbers are saved only in this browser
- Nothing you type is sent anywhere
- Choose kilograms and centimetres, or pounds and inches, at the top
Related tools
- BMI Calculator — body mass index
- Ideal Weight Calculator — your healthy range
- TDEE Calculator — daily calories
- Macro Calculator — protein, carbs and fat
- Heart Rate Zone Calculator — train in the right zone
