Body Fat Calculator
Estimate your body fat percentage with the U.S. Navy tape method — just a tape measure required.
How the Navy method works
Developed for the U.S. Navy by Hodgdon and Beckett, this method estimates body fat from a few circumference measurements. Against lab methods (DEXA, hydrostatic weighing) it is typically accurate within ±3-4% — remarkably good for a tape measure.
Women: BF% = 495 ÷ (1.29579 − 0.35004×log10(waist+hip−neck) + 0.22100×log10(height)) − 450
Body fat categories (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% |
| Obese | 25%+ | 32%+ |
How to measure correctly
- Neck: just below the larynx, tape sloping slightly downward to the front.
- Waist: men at the navel; women at the narrowest point. Relaxed, after exhaling.
- Hips (women): around the widest part of the buttocks.
- Measure on bare skin, same time of day, and average two readings.
Knowing your body fat also unlocks the more precise Katch-McArdle option in our BMR and TDEE calculators.
Frequently asked questions
What is a healthy body fat percentage?
For general health, roughly 10-20% for men and 18-28% for women. Athletes run lower; some essential fat (2-5% men, 10-13% women) is required for hormones and organ function.
How accurate is the Navy tape method?
Studies put it within about 3-4% of lab measurements for most people when measurements are taken carefully. Consistency matters more than absolutes — track the trend with identical technique.
Why does my smart scale say something different?
Bio-impedance scales are highly sensitive to hydration, food and time of day, swinging several percent in a single day. Neither method is a lab test; pick one and follow the trend.
How fast can I lose body fat?
A sustainable pace is 0.5-1% of body weight per week, which mostly comes from fat if protein and resistance training are in place. Faster than that increasingly costs muscle.
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, 1984.
- American Council on Exercise. Percent Body Fat Norms for Men and Women.