How do I check my body fat at home?
- 1Choose your sex and the method: tape measure (more accurate) or BMI-based.
- 2Enter your weight and height.
- 3For the tape method, measure your neck and waist (and hips for women) with a soft tape, relaxed and not pulled tight.
- 4Read your body fat %, your ACE fitness category, and your fat and lean mass.
How is body fat percentage calculated?
- 01Men (cm): body fat % = 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450
- 02Women (cm): body fat % = 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450
- 03BMI method (adults): body fat % = 1.20 × BMI + 0.23 × age − 10.8 × (1 for men, 0 for women) − 5.4
- 04Fat mass = weight × body fat % · Lean mass = weight − fat mass
The US Navy method (Hodgdon and Beckett, Naval Health Research Center, 1984) estimates body fat from body circumferences. Fat around the waist grows faster than the neck, so the difference between them — compared with your height — tracks body fat well. Women's fat is spread more to the hips, so their formula adds the hip measurement. It was checked against underwater weighing and is still used by the US armed forces.
The BMI method (Deurenberg et al., British Journal of Nutrition, 1991) uses your BMI, age and sex. It works on average for groups of people, but it can't see muscle, so a muscular person gets too high a figure. Use it only when you can't measure.
The categories come from the American Council on Exercise (ACE): essential fat, athletes, fitness, average and obese. Women naturally carry more fat than men, so their ranges are higher.
No home method is exact. For a lab-grade number, a DEXA scan or underwater weighing is needed. What matters most is the trend: measure the same way every 2–4 weeks.
Example: body fat from a tape measure
A man 175 cm tall and 70 kg, with a 38 cm neck and 85 cm waist, has about 16.9% body fat with the US Navy formula.
That is 11.9 kg of fat and 58.1 kg of lean mass — the “fitness” range for men.
Good to know
- Measure in the morning before eating, on bare skin, with the tape flat and snug but not pressing in.
- Measure each place twice and use the average — a 1 cm mistake at the waist changes the result by about 1 %.
- Track the trend every 2–4 weeks. If your waist shrinks while your weight stays the same, you are losing fat and building muscle.
- A waist over half your height is a sign of extra belly fat, whatever your BMI says.
Body fat calculator — common questions
What is a healthy body fat percentage?
For adults, about 14–24 % for men and 21–31 % for women (ACE “fitness” and “average” ranges). Athletes are lower; over 25 % (men) or 32 % (women) is in the obese range.
Body fat kaise check kare? (How do I check body fat at home?)
Ek naram tape se gardan aur kamar (auraton ke liye kulhe bhi) naapein aur upar daal dein — US Navy formula aap ka body fat % bata dega. (Measure your neck and waist — plus hips for women — with a soft tape and enter them above.)
How accurate is the US Navy body fat method?
Usually within about 3–4 % of a DEXA scan when measured carefully. It is less accurate for very lean or very muscular people.
Is body fat percentage better than BMI?
Yes, for one person. BMI only compares weight with height, so muscular people can look “overweight”. Body fat % shows how much of your weight is actually fat.
Where exactly do I measure my waist?
In the US Navy method men measure around the belly button and women at the narrowest point of the waist. Stand relaxed and measure after breathing out.
How can I lower my body fat?
Eat a little less than your maintenance calories, get enough protein (about 1.6 g per kg) and do strength training 2–3 times a week. Our calorie and macro calculators help plan it.
Sources
- Hodgdon JA, Beckett MB – Prediction of percent body fat for US Navy men and women from body circumferences and height (Naval Health Research Center reports 84-11 and 84-29, 1984)
- US Department of Defense – DoD Instruction 1308.03, DoD Physical Fitness/Body Composition Program (circumference method)
- Deurenberg P, Weststrate JA, Seidell JC – Body mass index as a measure of body fatness: age- and sex-specific prediction formulas (Br J Nutr, 1991)
- American Council on Exercise (ACE) – Percent body fat norms for men and women
Formulas last reviewed: September 30, 2026 ·How we check our formulas