How to measure
- Neck: just below the larynx (Adam’s apple), tape sloping slightly down at the front.
- Waist: men at the navel, women at the narrowest point.
- Hips (women only): at the widest point of the buttocks.
- Measure in the morning before eating, after a relaxed breath out, with the tape snug but not pressing in.
- Take two or three measurements and use the average. Measure the same way once a week to see the trend.
Body fat percentage chart
Categories from the American Council on Exercise (ACE). The cut-offs are a guide, not a diagnosis.
| 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 range | Above 32% | Above 25% |
The formula
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) + 0.221 × log10(height)) − 450. All measurements in centimetres.
How accurate is it?
The tape method is an estimate: compared with lab methods such as DEXA it is typically a few percentage points off, more for very muscular people or at high body fat. Smart scales (bioimpedance) can swing day to day with hydration. Whichever you use, watch the trend and always measure the same way at the same time.
What to do with your result
Body fat percentage tells you your lean mass, a better starting point than weight alone. When losing fat, the aim is to lose fat and keep muscle: that takes enough protein (protein calculator), a moderate deficit (calorie calculator) and strength training. More in cutting without losing muscle.
Frequently asked questions
What is a normal body fat percentage?
In the ACE categories the average range is 25-31% for women and 18-24% for men; the fitness range is 21-24% for women and 14-17% for men.
How accurate is the US Navy method?
It is a good estimate, not a lab measurement, and can be off by a few percentage points. It is ideal for tracking change when you measure the same way each time.
Why is my smart scale different?
Scales use bioimpedance, which shifts with hydration, food and exercise. The two methods can disagree; with both, the trend matters more than a single reading.
How do I lose body fat without losing muscle?
With a moderate calorie deficit, high protein (about 1.8-2.4 g per kg of body weight with training) and regular strength training.