Estimate your body fat percentage with a tape measure in about two minutes. This free calculator uses the U.S. Navy circumference method, with separate formulas for women and men, and shows a second estimate from your BMI so you can compare. It works in inches and pounds or centimeters and kilograms.
Body fat percentage chart for women and men
The American Council on Exercise (ACE) groups body fat into five ranges. Women carry more essential fat than men for hormonal and reproductive health, so every range sits higher for women. Your result row is highlighted after you calculate.
| Category |
Women |
Men |
| Essential fat |
10 to 13% |
2 to 5% |
| Athletes |
14 to 20% |
6 to 13% |
| Fitness |
21 to 24% |
14 to 17% |
| Average |
25 to 31% |
18 to 24% |
| Obese |
32% and up |
25% and up |
Source: American Council on Exercise body fat categories. The ranges are not age adjusted. Body fat tends to rise with age, so compare yourself mostly with your own past results.
How to measure for an accurate result
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Use a flexible tape that is snug on the skin but not pressing in. Measure on bare skin, relaxed, not after a big meal or workout.
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Neck: just below the larynx (Adam's apple), with the tape angled slightly down toward the front.
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Waist for women: at the narrowest point of the natural waist, usually just above the belly button.
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Waist for men: horizontally at the level of the belly button, after a normal breath out.
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Hips (women only): around the widest part of the buttocks, with feet together.
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Repeat each measurement two or three times and use the average. Measure at the same time of day each time you track.
The formulas this calculator uses
U.S. Navy circumference method
Developed by Hodgdon and Beckett at the Naval Health Research Center in 1984 and still used by the Department of Defense for body composition screening. Measurements are in inches and logarithms are base 10.
Women: %BF = 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387
Men: %BF = 86.010 x log10(waist - neck) - 70.041 x log10(height) + 36.76
BMI-based estimate (Deurenberg)
Deurenberg and colleagues (1991) estimated body fat from BMI, age and sex. It needs no tape, but it cannot tell muscle from fat, so it reads high for muscular people. We show it as a cross-check.
%BF = 1.20 x BMI + 0.23 x age - 10.8 x sex - 5.4 (sex: 1 for men, 0 for women)
Worked example
A woman who is 5 ft 6 in (66 in) tall, weighs 150 lb, is 42 years old, and measures a 13 in neck, 30 in waist and 40 in hips. Waist plus hips minus neck is 57 in. The Navy formula gives 163.205 x log10(57) minus 97.684 x log10(66) minus 78.387, which is about 30.4% body fat, at the top of the Average range. Her BMI is 24.2, so the Deurenberg estimate is about 33.3%. The two numbers often differ by several points; the tape method is usually the closer one for active adults.
Where body fat fits into a recovery routine
Body fat is one marker of fitness, not a score of your health or worth. The changes that move it are steady: enough protein, regular strength and aerobic training, sleep, and recovery that lets you keep training. Many people use a sauna or a cold plunge as part of that recovery routine because it helps them relax and stick with their habits. A sauna session does not burn fat on its own; the scale drop afterward is mostly water, so rehydrate. If you want to see what a session does use, try our sauna calorie calculator and sauna hydration calculator.
Frequently asked questions
What is a healthy body fat percentage for a woman?
By the ACE chart, about 21 to 24% is the fitness range and 25 to 31% is average for women. Below about 10 to 13% (essential fat) is too low for most women. The right target depends on your age, health and goals, so use your doctor's guidance for anything specific.
How accurate is the Navy body fat calculator?
For most adults, tape methods like the Navy formula land within a few percentage points of lab measurements. Accuracy drops for very lean athletes, very muscular builds, and larger bodies, and small measuring errors at the waist change the result. It is best for tracking your own trend over time with the same tape and technique.
Why does the calculator need hip size for women but not men?
Women tend to store more fat around the hips and thighs, so the Navy formula for women adds the hip measurement to improve accuracy. The men's formula uses only waist, neck and height.
Why is my BMI estimate different from my Navy result?
BMI only uses height and weight, so it cannot tell muscle from fat. Muscular people often get a BMI estimate that is too high. The Navy method uses body measurements, which reflect where fat is carried, so it is usually closer for active people.
How often should I measure my body fat?
Every two to four weeks is enough. Body fat changes slowly, and daily swings in water and food make frequent checks noisy. Measure at the same time of day, in the same way, and watch the trend.
Does using a sauna lower body fat?
Not directly. Most weight lost during a sauna session is water from sweating, which comes back when you rehydrate. Sauna use is best treated as part of your relaxation and recovery routine alongside training, diet and sleep.
Sources: 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 and 84-29 (1984). Deurenberg P, Weststrate JA, Seidell JC. Body mass index as a measure of body fatness: age- and sex-specific prediction formulas. British Journal of Nutrition, 1991. American Council on Exercise body fat percentage categories. Prepared by Logan McClure, Restore Suite. For general information only, not medical advice.
