Your body fat percentage is the share of your weight that is fat. It tells you more than weight or BMI alone, because two people with the same weight can have very different amounts of muscle and fat.
This calculator uses the US Navy method, which needs only a measuring tape. It is less exact than a DEXA scan, but it is free, quick and good for tracking changes over time.
How to measure
Use a soft tape. Keep it snug on the skin but don't squeeze. Stand relaxed and don't pull your stomach in.
- Neck: just below the Adam's apple (the bump in the throat), with the tape sloping slightly down at the front.
- Waist: men measure around the navel. Women measure at the narrowest part of the waist.
- Hips (women only): around the widest part of the buttocks.
- Height: without shoes.
Measure twice and use the average. Measure at the same time of day each time, ideally in the morning.
US Navy formula (measurements in cm)
Men: Body fat % = 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450
Women: Body fat % = 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450
Fat mass = Weight × body fat % ÷ 100
Lean mass = Weight − fat massExample
A man who is 170 cm tall and weighs 70 kg, with a 38 cm neck and an 85 cm waist:
- Body fat = 17.8%, which is in the Fit range (just below the average range that starts at 18%)
- Fat mass = 70 × 17.8% = 12.5 kg
- Lean mass (muscle, bone, water and organs) = 57.5 kg
A woman who is 160 cm tall and weighs 60 kg, with a 33 cm neck, 75 cm waist and 100 cm hips, gets about 30.8%, which is in the Average range, with 18.5 kg of fat mass.
Body fat categories (ACE chart)
| Category | Men | Women |
|---|---|---|
| Essential fat | 2 – 5% | 10 – 13% |
| Athletes | 6 – 13% | 14 – 20% |
| Fitness | 14 – 17% | 21 – 24% |
| Average | 18 – 24% | 25 – 31% |
| Obese | 25% and above | 32% and above |
Women naturally carry more fat than men, because the body needs it for hormones and pregnancy.
FAQ
How accurate is the US Navy method?
It is usually within a few percentage points of lab methods, but it can be further off for very lean, very muscular or very heavy people. Use it mainly to see whether your number is going up or down over time.
What is a healthy body fat percentage?
For most adults, the fitness and average ranges on the chart are considered healthy: roughly 14 to 24% for men and 21 to 31% for women. Studies show that South Asians often carry more body fat, especially around the belly, at the same weight as Europeans, so keeping your waist in check matters too.
Why does my smart scale show a different number?
Smart scales use a small electric current (bioimpedance). Their reading changes with how much water you have drunk, exercise and time of day. Different methods give different numbers, so compare results from the same method.
How can I reduce my body fat?
Eat slightly fewer calories than you burn, get enough protein and do strength training so you lose fat rather than muscle. The calorie calculator and protein calculator help you set your targets.