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Body Fat Calculator

Estimate your body fat percentage with the US Navy method, see your fat mass and lean body mass, and compare with the ranges for women and men.

  • Free to use
  • No sign-up
  • Numbers stay in your browser

Last updated:

Your measurements

Sex

Women also enter their hips.

years

Only used for the BMI estimate.

Height
ft
in
in

Just below the larynx.

in

At the navel for men, the narrowest point for women.

lb

Shows your fat mass and lean mass.

The boxes start with example numbers. Change them to your own, then press Calculate.

Your body fat

Body fat (US Navy method)
17.4% Fitness
US Navy method · range for men

Your body fat of 17.4% is in the fitness range for men (14–17.9%). The Navy method is an estimate, often a few percentage points away from a DEXA scan.

  • Body weight
    180.0 lb
    81.6 kg
  • Fat mass
    31.3 lb
    14.2 kg · 17.4%
  • Lean body mass
    148.7 lb
    67.4 kg · 82.6%
  • BMI
    25.8
    Overweight

Second estimate (BMI method): 21.7% (average range), worked out from your BMI and age. It is usually within about 4 points, so treat it as a rough check.

Body fat percentage range for men

Your body fat of 17.4% is marked. The ranges for women are different: see the table below.

Common body fat ranges

CategoryMenWomen
Essential fat2–5.9%10–13.9%
Athletes6–13.9%14–20.9%
Fitness14–17.9%21–24.9%
Average18–24.9%25–31.9%
Obese25% and over32% and over

American Council on Exercise (ACE) categories for adults. Your range is highlighted. Women have a higher essential fat, so the ranges are higher.

Example calculations

SexHeightNeckWaistHipsBody fat
Male5 ft 10 in15 in34 in—17.4%Fitness
Male6 ft 0 in16 in36 in—18.5%Average
Female5 ft 4 in12.5 in28 in38 in27.0%Average
Female5 ft 7 in13 in30 in40 in29.4%Average

Worked out with the same formula as the calculator.

How to measure body fat with a tape

  1. 1Stand up straight and relaxed. Use a soft tape and keep it snug, not tight.
  2. 2Neck: just below the larynx (Adam's apple), with the tape level.
  3. 3Waist: at the navel for men. At the narrowest point for women.
  4. 4Hips (women): at the widest point.
  5. 5Breathe out normally, do not pull your stomach in, and measure twice. Use the average.

Other ways to measure body fat

  • Skinfold calipersPinch the skin at set places on the body and use a formula. Cheap, but it takes practice.
  • Bioelectrical impedance (BIA)Smart scales and handheld devices send a tiny current through the body. Results change with how much water you have drunk.
  • DEXA scanA low-dose X-ray done at a clinic. More precise, but it costs more and needs an appointment.
  • Hydrostatic weighing and Bod PodMeasure body density in water or in an air chamber. Very precise, found in specialist centers.

How body fat is worked out

The US Navy method uses the logarithm (log10) of your tape measurements in centimeters.

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 + hips − neck) + 0.22100 × log10(height)) − 450
BMI method: body fat % = 1.20 × BMI + 0.23 × age − 10.8 × sex − 5.4 (sex = 1 for men, 0 for women)

Fat mass = weight × body fat %. Lean body mass = weight − fat mass.

What your body fat percentage means

10% body fat
Men: Athletes · Women: Essential fat
12% body fat
Men: Athletes · Women: Essential fat
15% body fat
Men: Fitness · Women: Athletes
18% body fat
Men: Average · Women: Athletes
20% body fat
Men: Average · Women: Athletes
25% body fat
Men: Obese · Women: Average
30% body fat
Men: Obese · Women: Average

Body fat or BMI?

BMI compares weight with height, so it cannot tell muscle from fat. Body fat percentage looks at how much of your weight is fat.

A muscular person can have a high BMI and a healthy body fat, so using both gives a fuller picture. See the BMI Calculator.

What is included

  • Body fat percentage by the US Navy method
  • Your category for women or men (ACE)
  • Fat mass and lean body mass
  • A second estimate from your BMI and age
  • How to measure, and example calculations
  • US units and metric units

Important to know

The Navy method is an estimate and can be a few percentage points away from a DEXA scan. It is for healthy adults, not for children or pregnant women, and it is not medical advice. Measure the same way each time to track changes.

Use this free body fat calculator, also called a body fat percentage calculator, to estimate how much of your weight is fat. Enter your sex, height and tape measurements of your neck and waist (plus your hips if you are a woman), in US or metric units, and you get your body fat percentage by the US Navy method and your category. Add your weight to see your fat mass and lean body mass, and your age for a second estimate from your BMI. Tables show the body fat ranges for women and men, worked examples, and how to take the measurements with a tape. It is free and instant, and your numbers stay in your browser.

What is body fat?

Body fat is the fat tissue your body stores. Some of it is essential fat, the least the body needs to work normally, which is about 2–5% of body weight in men and 10–13% in women. The rest is storage fat, which sits under the skin and, as visceral fat, inside the belly around the organs. A body fat percentage is the share of your weight that is fat. The rest, your lean body mass, is muscle, bone, organs and water.

The US Navy method, step by step

The US Navy method estimates body fat from a few tape measurements instead of special equipment. It uses the difference between your waist and neck (and your hips, for women), together with your height. More fat around the waist for the same neck size and height means a higher body fat percentage.

Men: % = 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450
Women: % = 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450
All measurements are in centimeters. The calculator converts inches for you.

Example: a man who is 180 cm tall with a 38 cm neck and an 85 cm waist has an estimated body fat of about 16.1%, which falls in the fitness range. If he weighs 80 kg, that is about 12.9 kg of fat and 67.1 kg of lean mass. A woman who is 165 cm tall with a 32 cm neck, a 75 cm waist and 98 cm hips has an estimated body fat of about 28.9%, in the average range.

The BMI method for a second estimate

If you enter your weight and age, the calculator also gives a second, rougher estimate from your BMI. It uses an equation published by Deurenberg and colleagues in 1991 for adults: body fat % = 1.20 × BMI + 0.23 × age − 10.8 × sex − 5.4, where sex is 1 for men and 0 for women. The authors found it usually lands within about 4 percentage points of a density measurement, and that it slightly overestimates body fat in people with obesity. For a 30-year-old man with a BMI of 25.8 it gives 21.7%, compared with 17.4% from the tape measurements, which shows why the tape method is the main figure.

Healthy body fat percentages for women and men

The calculator uses the categories of the American Council on Exercise (ACE). Women naturally carry more essential fat than men, so their ranges are higher.

  • Men: essential fat 2–5.9%, athletes 6–13.9%, fitness 14–17.9%, average 18–24.9%, and 25% or more is obese.
  • Women: essential fat 10–13.9%, athletes 14–20.9%, fitness 21–24.9%, average 25–31.9%, and 32% or more is obese.

“Average” here is the name of an ACE band, not the average body fat of the population. The bands are a general guide and do not suit everyone, and what is healthy for you also depends on your age, fitness and health.

Visceral fat and a calculator

Visceral fat is the fat stored inside the belly, between the organs. It cannot be worked out from a few tape measurements, because it needs a scan to see it. A large waist measurement can be a clue that there is more of it, but only a doctor can say. This calculator estimates your total body fat, not your visceral fat.

Tape tests used by the military

Military services use tape measurements of this kind to check body composition, but each has its own rules and limits. This calculator gives the Navy-method estimate and the civilian ACE categories. It does not check whether you meet any military standard.

How accurate is the estimate?

The Navy method is handy and free, but it is only an estimate and is often a few percentage points away from scans such as DEXA. It works best for adults of average build, and small errors with the tape can change the result by a percentage point or more. Measure in the same way each time if you want to track changes. For your overall weight, see the BMI Calculator. For a healthy weight for your height, try the Ideal Weight Calculator.

Sources

The rules, rates and ranges on this page come from these sources. Always check the current figures with the organization itself before you rely on them.

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Frequently Asked Questions

How do I calculate my body fat percentage?

Measure your height, neck and waist (and hips if you are a woman) and enter them. The US Navy formula uses the logs of these measurements to estimate your body fat. A man who is 180 cm tall with a 38 cm neck and an 85 cm waist gets about 16.1%. The calculator does the sum for you.

How do I measure body fat?

At home, the easiest way is a tape measure, as in this calculator. Other ways are skinfold calipers, bioelectrical impedance scales, and clinic tests such as a DEXA scan, hydrostatic weighing or a Bod Pod, which are more precise but cost more.

What is the US Navy method?

It is a formula that estimates body fat from height and tape measurements of the neck and waist (plus the hips for women). It needs no special equipment, which is why it is so popular.

What is a healthy body fat percentage?

By ACE categories, 14% to 24.9% is fitness to average for men, and 21% to 31.9% for women. Women naturally carry more essential fat. These are general ranges, and what is healthy for you depends on your age and health.

What is the average body fat percentage for women and men?

"Average" is the name of one ACE band: 18% to 24.9% for men and 25% to 31.9% for women. It is not the average of the whole population. Fitness is 14% to 17.9% for men and 21% to 24.9% for women.

How accurate is this calculator?

It is an estimate and is often a few percentage points away from professional tests such as DEXA scans. It is useful for tracking changes over time if you always measure in the same way.

What is the BMI method estimate?

If you enter your weight and age, the calculator also works out body fat from your BMI with the Deurenberg equation: 1.20 × BMI + 0.23 × age − 10.8 × sex − 5.4 (sex is 1 for men and 0 for women). It is usually within about 4 points and is less reliable than the tape measurements, so it is shown as a second check.

Is body fat better than BMI?

They measure different things. BMI only uses height and weight, so it cannot tell muscle from fat. Body fat percentage looks at how much of your weight is fat, but it is harder to measure precisely. Using both gives a fuller picture.

How do I measure my waist, neck and hips?

Neck just below the larynx, waist at the navel for men and at the narrowest point for women, and hips at the widest point. Keep the tape snug but not tight, breathe out normally and do not pull your stomach in. Measure twice and use the average.

What is visceral fat, and can this calculator measure it?

Visceral fat is fat stored inside the belly around the organs. A calculator cannot measure it, because it needs a scan. This calculator estimates your total body fat. A large waist can be a clue, so ask a doctor if you are worried.

Does the Army use the same formula?

Military services use tape tests of a similar kind, but each has its own rules and limits. This calculator gives the Navy-method estimate and the civilian ACE categories. It does not check whether you meet any military standard.

What are fat mass and lean body mass?

Fat mass is your weight multiplied by your body fat percentage. Lean body mass is the rest: muscle, bone, organs and water. At 180 lb and 17.4% body fat, fat mass is about 31.3 lb and lean body mass about 148.7 lb.

Can I use this calculator for children or while pregnant?

No. It is meant for healthy adults. It is not suitable for children or for pregnant women, and it is not medical advice. Speak to a doctor about your own health.

Can I save, share or print my results?

Yes. After you press Calculate, use Copy link to get a link that opens the calculator with the same numbers, or Print for a clean printout. The numbers sit after the # in the link, a part of the address that browsers do not send to our server.

Are my numbers saved or shared?

No. The calculation happens in your browser, and the numbers you type are not stored or sent to any server.