Estimate your body fat percentage with the U.S. Navy tape-measure method, see your body-fat category, and get your fat and lean mass — with the figure responding live to your result.
Fat mass = weight × body fat %; lean mass is everything else (muscle, bone, organs, water). Enter your weight to see both. All figures are estimates, not a diagnosis.
Your body fat percentage is the share of your total body weight that is made up of fat, with the rest being lean (fat-free) mass such as muscle, bone, organs and water. Unlike body weight or BMI, it describes your body composition directly, so it tells you what your weight is actually made of. A small amount of fat, called essential fat, is necessary for hormones, temperature regulation and protecting organs; the rest is storage fat.
This calculator uses the U.S. Navy circumference method to estimate your body fat from your height and a few tape-measure readings. It is a fast, equipment-free estimate — useful for tracking changes over time rather than as an exact clinical figure.
Tip: pair this with our BMI Calculator and BMR Calculator to see your weight status and daily calorie needs alongside your body composition.
There is no single official standard, but the categories below from the American Council on Exercise (ACE) are widely used. Healthy ranges differ between men and women because women naturally carry more essential fat.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average / acceptable | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
The U.S. Navy method estimates body fat from the relationship between your height and the circumference of certain body parts, where fat tends to accumulate. Men need height, neck and waist; women also need the hip measurement. The values are combined using a validated logarithmic equation, shown in the formula box above.
Each method trades accuracy for convenience. The tape method here is quick and free; other options include:
BMI compares your weight to your height and cannot tell muscle from fat, so a muscular person can be labelled overweight despite low body fat. Body fat percentage estimates how much of you is actually fat, which is often more meaningful for fitness. Both are screening tools rather than diagnoses, and they work best together — you can check yours with our BMI Calculator.
Ranges differ by sex. Using ACE categories, the fitness range is about 14–17% for men and 21–24% for women, and the average range is roughly 18–24% for men and 25–31% for women. Some essential fat is required for health.
It uses the U.S. Navy circumference method, estimating body fat from your height and the circumference of your neck and waist (plus hips for women) with a validated logarithmic formula. It needs only a tape measure.
For most people it lands within about 3–4 percentage points of methods like DEXA, provided you measure carefully and consistently. It is an estimate, not a clinical measurement.
Use a flexible tape on bare skin, snug but not compressing. Measure the neck below the larynx, the waist at the navel (men) or narrowest point (women), and the hips at the widest point (women). Average two or three readings.
They measure different things. BMI compares weight to height; body fat percentage estimates how much of you is fat. Body fat % is often more informative for fitness, but both are screening tools, not diagnoses.
Fat mass is your weight multiplied by your body fat percentage. Lean (fat-free) mass is everything else — muscle, bone, organs and water. This calculator shows both when you enter your weight.
The circumference method originates from U.S. Navy research (Hodgdon & Beckett). Category ranges follow the American Council on Exercise (ACE). For general guidance on body composition and healthy weight see the CDC healthy weight resources and the NHS healthy weight information. This page is for general information and is not medical advice.