Estimate your body fat percentage without any special equipment. Enter a few tape measurements and this calculator uses the US Navy method to give your body fat percentage and category.
1. Choose your gender and enter your age and height. 2. Measure your neck and waist with a tape. 3. Women also enter hip measurement, then click Calculate Body Fat %.
Your weight alone does not tell you how healthy you are, because it does not say how much of you is fat and how much is muscle. Two people can weigh the same, but one can be fit and muscular while the other carries too much fat. This free body fat calculator estimates your body fat percentage using the US Navy method, which needs only a tape measure: your height, neck and waist (and hip for women). It is the simplest way to track fat loss, because the scale cannot tell fat loss from muscle loss.
Body fat percentage is a better health guide than weight or BMI for many people. For men, 10 to 20 percent is usually fit, and above 25 percent is considered too high. For women, 20 to 30 percent is usually fit, and above 32 percent is considered too high. Athletes have lower percentages, and a small amount of fat is essential for health — below about 5 percent for men and 13 percent for women is dangerous.
Suppose a man is 175 cm tall, with a neck of 38 cm and a waist of 85 cm. The waist minus the neck is 47 cm, and the US Navy formula gives a body fat percentage of about 16.9 percent, which falls in the Fitness category for men. If the same man loses 5 cm from his waist, bringing it to 80 cm, his body fat falls to about 12.9 percent, which is in the Athlete category. Try it in the calculator above and check that your result matches about 16.9 percent.
Take a woman who is 165 cm tall, with a neck of 32 cm, a waist of 75 cm and hips of 95 cm. The US Navy formula gives a body fat percentage of about 27.4 percent, which is in the Average category for women. If she reduces her waist to 70 cm, her body fat falls to about 24.9 percent, which is in the Fitness category. Enter these numbers in the calculator — height 165, neck 32, waist 75, hip 95, Female — and check that your result matches about 27.4 percent.
The US Navy method was developed by the US Navy to estimate body fat from tape measurements. For men, the formula is: body fat % = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450. For women, it is: body fat % = 495 / (1.29579 - 0.35004 x log10(waist + hip - neck) + 0.22100 x log10(height)) - 450. All measurements are in centimetres, so enter them exactly as you measured them with your tape. The method is accurate to about 3 to 4 percent for most people, which is good enough for tracking progress over months.
Measure the waist correctly. Measure at the belly button, with the tape level and snug but not tight, and do not hold your stomach in. Measure the neck below the Adam's apple. Keep the tape level and relaxed. Measure hips at the widest point for women, standing straight with feet together. Measure at the same time of day. Morning measurements, before eating, are the most consistent. Track the trend, not one number. A single reading can be off by a few percent, so check again every month and watch the direction.
Measuring the waist too high or too low. The waist is measured at the belly button, not at the belt line. Pulling the tape too tight. A tight tape gives a smaller waist and a falsely low body fat reading. Holding your stomach in. Breathe out normally and relax, or the reading is meaningless. Using inches as centimetres. This calculator needs centimetres; 85 cm is not 85 inches. Expecting lab accuracy. The US Navy method is an estimate with about 3 to 4 percent error, so use it to track change, not as a medical diagnosis.
Pro Tip: Your waist measurement alone is a strong health signal: for men, a waist above 102 cm (40 inches) and for women above 88 cm (35 inches) is linked to higher health risks.
Note: This calculator gives an estimate only and is not medical advice. For an exact body fat measurement, ask for a DEXA scan or a professional body composition test.
What is body fat percentage? It is the share of your body weight that is fat, rather than muscle, bone and water. For example, if you weigh 80 kg and your body fat is 20 percent, you carry about 16 kg of fat.
What is a healthy body fat percentage? For men, 10 to 20 percent is usually fit and above 25 percent is too high. For women, 20 to 30 percent is usually fit and above 32 percent is too high. A small amount of fat is essential for health.
How does the US Navy method work? It estimates body fat from tape measurements: height, neck and waist for men, plus hips for women. It uses a formula based on the logarithm of the measurements, and is accurate to about 3 to 4 percent.
Is body fat percentage better than BMI? Often yes. BMI only uses weight and height, so a muscular person can have a high BMI while being very fit. Body fat percentage separates fat from muscle, so it shows fitness more clearly.
How do I measure my waist correctly? Measure at the belly button with a soft tape, level and snug but not tight. Breathe out normally and do not hold your stomach in.
How often should I check my body fat? Once a month is enough. Body fat changes slowly, so weekly checks mostly show measurement error, not real change.
Can I reduce body fat without losing muscle? Yes. Eat enough protein, do strength training, and lose weight slowly — no more than 0.5 to 1 kg per week. Fast weight loss usually loses muscle too.
Is this calculator accurate? It is an estimate with about 3 to 4 percent error. For a precise result, use a DEXA scan, hydrostatic weighing or a professional body composition test.
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