Body Fat Calculator (US Navy Method)
Unlike BMI, body fat percentage tells muscle from fat. Using a tape measure, your height, neck and waist (plus hip for women) are turned into your body-fat percentage. For example, a man who is 180 cm tall with a 40 cm neck and a 90 cm waist has a body fat percentage of about 18%.
Enter your measurements — your body fat percentage appears here instantly.
The tape-measure method is an estimate; measurement error and body type affect the result.
Your inputs never leave your device; the calculation runs in your browser and nothing is sent to a server.
Body fat percentage ranges
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletic | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| High | 25% and above | 32% and above |
This is the widely used (ACE) classification; the ideal range varies with age, genetics and your goals. Dropping below essential fat is unhealthy.
For informational purposes only; not medical advice. Consult a doctor or dietitian about body composition and health goals.
Body fat percentage is the share of your total weight that is made up of fat tissue. Because BMI only compares height and weight, it cannot tell muscle from fat; that is why a muscular athlete can look "overweight" on a BMI chart. Body fat percentage gives a more direct sense of body composition, so it is often a more meaningful measure for fitness and health tracking.
This calculator uses the US Navy tape-measure formula — a common, practical method that needs no equipment. For men it measures height, neck and waist; for women it also adds the hip circumference. The differences between these measurements are converted into a body-fat percentage. If you enter your weight too, your fat mass and lean mass are also calculated in kilograms.
How to Measure Correctly
The accuracy of the result depends on the accuracy of your measurements. Measure your waist at the level of your navel, without pulling your stomach in or holding your breath. Measure your neck just below the larynx, holding the tape slightly angled. Measure your hip at its widest point. The tape should be snug against the skin but not tight; taking the measurement a few times and using the average reduces error.
What Is the Healthy Range?
A certain amount of fat is required for vital functions; this is called essential fat and is roughly 2-5% in men and 10-13% in women. Because of hormonal functions, a healthy fat percentage is naturally higher in women than in men. The fitness and average ranges are reasonable targets for most people; both very high and extremely low body fat carry health risks. As you age, the range considered healthy also shifts up somewhat.
Limitations of the Method
The tape-measure method is a practical estimate, not a clinical measurement. A DEXA scan, hydrostatic weighing or bioelectrical impedance (BIA) devices can give a more precise result. Water retention, meal timing and measurement error can cause day-to-day swings. So rather than fixating on a single value, it is more reliable to measure regularly under the same conditions and watch the trend over time.
Make Tracking Easier
The foundation of changing your body composition is consistent nutrition and movement. When you calculate your daily calorie needs and log what you eat, the path to your goal becomes visible; measuring your body fat percentage at regular intervals lets you track your progress.
Frequently asked
How is body fat percentage calculated?
This calculator uses the tape-measure method developed by the US Navy. For men it measures height, neck and waist; for women it also adds the hip circumference, and the differences between these measurements are converted into a body-fat percentage with a formula. The method needs no equipment beyond a tape measure; the result is an estimate.
What is a healthy body fat percentage?
The healthy range varies by sex and age. The fitness range for men is roughly 14-17% and the average range 18-24%; for women the fitness range is about 21-24% and the average 25-31%. Essential fat (2-5% in men, 10-13% in women) is required for vital functions, and dropping below it is unhealthy.
How accurate is the tape-measure method?
The tape-measure (US Navy) method is a practical estimate; measured correctly it gives a reasonable result for most people, but it is not as precise as clinical methods such as a DEXA scan or hydrostatic weighing. Measurement error, water retention and body type affect the result. It makes the most sense to use the value as an indicator for tracking change over time.
Is body fat percentage or BMI better?
They measure different things. BMI looks only at height and weight and cannot tell muscle from fat, so a muscular person can look overweight by BMI. Body fat percentage gives a more direct sense of body composition, so it is often more informative for fitness and health tracking. Reading the two together is the healthiest approach.
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