Estimate your body fat percentage with a tape measure. This free body fat calculator uses the US Navy method (neck, waist and, for women, hips), checks it against a BMI-based estimate, and shows your fat mass, lean body mass and fitness category.
Body fat formulas
Worked example
A man 170 cm tall with a 38 cm neck and 85 cm waist: waist − neck = 47 cm. BF% = 495 / (1.0324 − 0.19077 × 1.672 + 0.15456 × 2.230) − 450 ≈ 17.8%, in the fitness range. At 70 kg that is about 12.5 kg of fat and 57.5 kg of lean mass.
Body fat 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% |
| Obese | 32% and above | 25% and above |
For general information only, not medical advice. Talk to a doctor or registered dietitian before major changes to your diet or training, especially if you are pregnant, under 18, or have a health condition.
Frequently asked questions
How accurate is the US Navy body fat method?
For most people it is within about 3–4 percentage points of DEXA scans. Accuracy depends on measuring in the same places every time.
Where do I measure my waist and neck?
Measure the neck just below the larynx (Adam’s apple). Men measure the waist at the navel, women at the narrowest point. Women also measure the widest part of the hips.
What is a healthy body fat percentage?
Roughly 14–24% for men and 21–31% for women is fit to average. Essential fat is about 2–5% for men and 10–13% for women.
What is lean body mass?
Everything that is not fat: muscle, bone, organs and water. It equals your weight minus your fat mass.
Why do the two estimates differ?
The BMI-based formula only uses height, weight, age and sex, so it cannot see muscle. The tape method uses your body shape and is usually better for active people.
Related tools
Free educational tool by HawkInc. Results are calculated in your browser and rounded for display; check critical work by hand or with a second method.