How to use this tool
- Measure your neck just below the larynx, and your waist at the navel (women also measure the widest part of the hips).
- Choose units and enter height and measurements.
- Read your estimated body fat, category and waist-to-height ratio.
How to measure
Use a flexible tape, snug but not compressing the skin. Measure the neck just below the Adam's apple, sloping slightly down at the front. Measure the waist at the navel for men, and at the narrowest point for women if the Navy protocol is followed, after breathing out normally. Take each measurement twice and use the average.
Body fat ranges (ACE)
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Above average | 25%+ | 32%+ |
Waist-to-height ratio
UK NICE guidance recommends keeping your waist to less than half your height. A ratio of 0.5 to 0.59 indicates increased health risk and 0.6 or more high risk, for adults of all ethnicities. It is a simple, useful check alongside BMI.
Frequently asked questions
How accurate is the Navy body fat method?
It is usually within about 3–4 percentage points of laboratory methods such as DEXA, but less accurate at the extremes.
What is a healthy body fat percentage?
Roughly 14–24% for men and 21–31% for women, according to ACE norms.
Where do I measure my waist?
At the navel, after breathing out normally.
What waist size is healthy?
Under half your height. For someone 170 cm tall, under 85 cm.
Sources and references
- Hodgdon JA, Beckett MB. Prediction of percent body fat for U.S. Navy men and women from body circumferences and height. Naval Health Research Center Report 84-11, 1984
- American Council on Exercise: Percent body fat norms
- NICE guideline NG246: waist-to-height ratio