Body Fat Percentage Calculator
Estimate body fat percentage with the US Navy tape-measure method.
About the Body Fat Calculator
Estimate your body fat percentage with nothing more than a tape measure. Enter your height, neck and waist (plus hips for women) and the calculator applies the US Navy circumference formula to show your body fat percentage and category — and, if you add your weight, your fat mass and lean body mass.
Body fat percentage is often more useful than BMI because it separates fat from muscle, bone and water.
How to use the Body Fat Calculator
- 1Choose your units and select your sex.
- 2Measure your neck just below the Adam’s apple, and your waist at the navel (men) or at its narrowest point (women).
- 3Women: also measure your hips at the widest point.
- 4Enter the measurements — and your weight if you want fat and lean mass.
Body fat percentage categories
The American Council on Exercise (ACE) uses these general ranges:
- Essential fat: women 10–13%, men 2–5%
- Athletes: women 14–20%, men 6–13%
- Fitness: women 21–24%, men 14–17%
- Average: women 25–31%, men 18–24%
- Obese: women 32% and above, men 25% and above
Tips for accurate measurements
Measure in the morning before eating, keep the tape level and snug without squeezing the skin, and take each measurement two or three times to use the average. Done carefully, the US Navy method usually lands within a few percentage points of lab methods such as DEXA scans.
Frequently asked questions
How does the US Navy body fat formula work?
It estimates body density from the difference between your waist (and hip) and neck measurements relative to your height, then converts that into a body fat percentage.
Is this more accurate than BMI?
It measures something different. BMI only uses height and weight, while this method reflects where your body stores fat, so it’s usually better at telling muscle from fat.
What is a healthy body fat percentage?
For most adults, roughly 21–31% for women and 14–24% for men falls in the fitness-to-average range. Very low body fat can be unhealthy too.
Is Body Fat Calculator free to use?
Yes — Body Fat Calculator is completely free with no signup, no limits and no hidden costs.
Is my data private and secure?
Everything runs entirely in your browser — your files and text never leave your device, ensuring complete privacy.
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