Body fat percentage is the share of your total body weight that is fat. A typical adult has a figure somewhere between the high teens and the low thirties, depending on sex, age and fitness, and you can estimate yours at home with a tape measure using the US Navy method.
Unlike a weight on the scales, body fat percentage separates fat from everything else: muscle, bone, organs and water. That is why two people of the same height and weight can have very different figures.
What body fat percentage actually means
Your body weight is made up of fat mass and lean mass. Body fat percentage is fat mass divided by total weight, multiplied by 100. Some fat is essential for hormones, insulation and protecting organs, so zero is neither possible nor healthy. Women naturally carry more essential fat than men.
If you weigh 80 kg and have 15 kg of fat, your body fat is 15 ÷ 80 × 100 = 18.75%, and your lean mass is 65 kg.
How body fat is measured
Methods vary a lot in cost and accuracy. None is perfect, and different methods can give different numbers for the same person on the same day.
- Tape measurements (US Navy method): uses height, neck and waist, plus hips for women. Cheap and repeatable, but only an estimate.
- Skinfold callipers: pinch thickness at several sites. Accuracy depends heavily on the person taking the readings.
- Bioelectrical impedance (smart scales, handheld devices): passes a small current through the body. Results shift with hydration, meals and exercise.
- DEXA and similar scans: clinical or specialist methods that image the body. Generally more detailed, but costly and not needed for most people.
For tracking at home, consistency matters more than the method. Measure at the same time of day, in the same conditions, and judge the trend over weeks rather than a single reading.
Typical body fat ranges
Different organisations publish different ranges. A commonly quoted set comes from the American Council on Exercise (ACE), which our Body fat percentage tool uses for its category label:
| 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% and over | 32% and over |
Ranges are broad guides, not targets. Body fat tends to rise a little with age, and a healthy figure for one person can look different for another. If you are worried about your figure, speak to a GP or other health professional.
A worked example with the US Navy method
The Navy method uses circumference measurements, taken with a flexible tape. Measure the neck just below the larynx, the waist at the navel (and the hips at their widest point for women), and your height without shoes.
Take a man who is 178 cm tall, weighs 80 kg, with a 38 cm neck and 88 cm waist. The calculator estimates:
- Body fat: about 18.7%
- Fat mass: about 15 kg
- Lean mass: about 65 kg
- Category: average
For a woman who is 165 cm tall, weighs 65 kg, with a 32 cm neck, 74 cm waist and 98 cm hips, the estimate is about 28.4%, with roughly 18.5 kg of fat and 46.5 kg of lean mass. Tape measurements can be a few points out, so treat the result as a rough guide.
Body fat percentage versus BMI
BMI is a simple ratio of weight to height squared (kg ÷ m²). The NHS adult ranges are under 18.5 underweight, 18.5 to 24.9 healthy, 25 to 29.9 overweight and 30 or more obese. It cannot tell fat from muscle, and thresholds differ for some ethnic groups. Our guide to BMI explained: what it tells you and what it doesn't covers those limits in more detail.
A muscular person can have a high BMI and a modest body fat percentage. Someone with a “healthy” BMI can still carry relatively more fat and less muscle. Using both numbers, alongside waist size and how you feel, gives a fuller picture than either alone.
If you are working on your numbers, your calorie needs are a sensible next step. See Calories and TDEE: how many calories do you need? and Macros for beginners: protein, carbs and fat.
Note: This is general information, not medical advice. Our tools give estimates only. Speak to a GP or registered dietitian before making major changes to your diet or exercise.
Try the calculator
Enter your measurements into the Body fat percentage calculator for an estimate, then compare it with your BMI result.
Open the free Body fat percentage
Frequently asked questions
Is the US Navy body fat method accurate?
It is a convenient estimate, but it can be several points out, especially if you carry weight unevenly or measure inconsistently. It is best used to track change over time.
What is a healthy body fat percentage?
It depends on age and sex, and organisations use different ranges. As a rough guide, the “fitness” and “average” categories in the table above cover many healthy adults. Ask a health professional about your own situation.
How often should I measure my body fat?
Every few weeks is plenty. Daily changes mostly reflect water and food, not fat.
Can I have a normal BMI and still have high body fat?
Yes. BMI ignores body composition, so someone with little muscle can sit in the healthy BMI range while carrying a higher share of fat.