Body Fat Calculator
Estimate your body fat percentage at home with just a tape measure. This free calculator uses the U.S. Navy method, based on your height, neck and waist (plus hips for women). Add your weight to also see your fat mass and lean body mass.
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What is body fat percentage?
Body fat percentage is the share of your total body weight that comes from fat. For example, if you weigh 80 kg and have 20% body fat, 16 kg of your weight is fat and the other 64 kg is lean mass, which includes muscle, bone, organs and water. Your body needs some fat to store energy, protect organs and make hormones, but too much, especially around the waist, raises the risk of heart disease, type 2 diabetes and high blood pressure.
Body fat percentage often tells you more about your health and fitness than your weight alone, because two people with the same weight can have very different amounts of fat and muscle.
How to measure yourself correctly
Use a flexible cloth or plastic tape measure and take each measurement two or three times, then use the average. Measure in the morning before eating, and keep the tape snug against the skin without squeezing.
Neck: measure just below the Adam's apple (larynx), with the tape sloping slightly down towards the front. Waist: men should measure horizontally at the level of the navel, and women at the narrowest part of the waist, after breathing out normally. Do not pull your stomach in. Hips (women only): measure around the widest part of the buttocks. Height: stand straight against a wall without shoes.
If you use imperial units, enter your height in total inches. For example, 5 ft 7 in is 67 inches.
U.S. Navy body fat formula
This calculator uses the circumference formula developed by the U.S. Navy, with all measurements in centimetres:
Men: Body fat % = 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450
Women: Body fat % = 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450
Example: A man who is 175 cm tall with a 38 cm neck and 85 cm waist has an estimated body fat of about 16.9%, which falls in the fitness range. If he weighs 75 kg, that is about 12.7 kg of fat mass and 62.3 kg of lean mass.
Body fat percentage chart
These categories from the American Council on Exercise (ACE) are widely used to describe body fat levels:
| 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%+ |
Women naturally carry more essential fat than men, mainly for hormonal and reproductive health, which is why their ranges are higher.
Healthy body fat by age
Body fat tends to rise slightly with age. Research-based guidelines suggest these healthy ranges for adults:
| Age | Men | Women |
|---|---|---|
| 20–39 | 8–19% | 21–32% |
| 40–59 | 11–21% | 23–33% |
| 60–79 | 13–24% | 24–35% |
How accurate is the U.S. Navy method?
For most adults, the Navy method gives an estimate within about 3–4 percentage points of lab methods, which is good for a free test you can do at home. It can be less accurate for very muscular people, people with an unusual fat distribution, and children or teenagers. Consistency matters more than perfect accuracy: measure the same way every few weeks and watch the trend.
Other ways to measure body fat include DEXA scans (very accurate but expensive), skinfold calipers (accurate when done by a trained person), and bioelectrical impedance scales (convenient, but readings change with hydration).
Body fat vs BMI
BMI only uses height and weight, so it cannot tell muscle from fat. A muscular person may have a high BMI but low body fat, while someone with a normal BMI can still carry too much fat around the waist. Using both together gives a much clearer picture. Check yours with our BMI Calculator.
How to reduce body fat
Lasting fat loss comes from a small, steady calorie deficit combined with exercise that protects your muscle. Eat enough protein at every meal, fill half your plate with vegetables, choose whole grains over refined flour, and cut back on sugary drinks and fried snacks. Add strength training two to three times a week alongside regular walking or cardio, and aim for 7–8 hours of sleep. You cannot target fat loss from one body part, such as the belly, with exercises alone. Use our BMR Calculator and Calorie Calculator to set your daily calories, and the Macro Calculator to plan your protein.
Frequently Asked Questions
What is a healthy body fat percentage?
For most adults, a healthy range is roughly 8–24% for men and 21–35% for women, depending on age. The fitness range is 14–17% for men and 21–24% for women.
How can I measure body fat at home?
The easiest way is the U.S. Navy method used on this page. You only need a tape measure to measure your neck, waist and, for women, hips, along with your height.
Why do women have a higher body fat percentage than men?
Women need more essential fat for hormone production and reproductive health. This is normal, so women's healthy ranges are around 7–10 percentage points higher than men's.
What is lean body mass?
Lean body mass is everything in your body except fat, including muscle, bone, organs and water. It is calculated by subtracting your fat mass from your total weight.
How often should I check my body fat?
Every 2–4 weeks is enough. Body fat changes slowly, and measuring too often can be misleading because of small day-to-day changes in water and food.
Can I lose belly fat only?
No. Spot reduction does not work. Fat is lost from the whole body through a calorie deficit, regular exercise and good sleep, and belly fat usually reduces as overall body fat goes down.