Body Fat Percentage Calculator
Estimate your body fat percentage with just a tape measure. Uses the US Navy circumference method, then shows fat mass, lean mass and where you fall in common fitness categories.
Estimated body fat
This calculator gives general estimates for information only and is not medical advice.
How to measure for the body fat calculator
- Measure your neck just below the larynx (Adam's apple), with the tape sloping slightly down toward the front.
- Measure your waist: men at the navel, women at the narrowest point. Women also measure the hips at the widest point.
- Keep the tape snug but not compressing the skin, measure relaxed (not sucking in), and take each measurement twice.
About the US Navy method
The US Navy method estimates body fat from body circumferences and height. It was developed to give a quick, equipment-free estimate and is used for military fitness standards. Studies typically find it within about 3–4 percentage points of laboratory methods like DEXA for most people, which makes it useful for tracking changes over time.
The categories shown follow the American Council on Exercise ranges. For men: essential fat 2–5%, athletes 6–13%, fitness 14–17%, average 18–24% and obese 25% and above. For women: essential fat 10–13%, athletes 14–20%, fitness 21–24%, average 25–31% and obese 32% and above.
Body fat percentage is more informative than BMI because it separates fat from muscle, but any single estimate has error. Measure at the same time of day under the same conditions and watch the trend rather than any one reading.
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Frequently asked questions
How accurate is the Navy body fat formula?
Typically within about 3–4 percentage points of lab methods for most people. It is less accurate for very muscular or very lean individuals.
What is a healthy body fat percentage?
For men roughly 14–24% and for women 21–31% fall in the fitness and average ranges. Very low or very high values carry health risks.
Why does it need my neck measurement?
The formula uses the difference between waist (and hip for women) and neck to separate fat from frame size.
Is this medical advice?
No. It is an estimate for general information. Talk to a healthcare provider about your health goals.