This body fat calculator estimates what share of your weight is fat, using only a tape measure and the US Navy formula. Men measure neck and waist; women add the hips. Along with height and weight, the result gives body fat percentage, fat mass in kg, lean mass and the range you fall in.
Tape methods are not lab scans, but done carefully they land within about 3 to 4 percentage points of one, and they are good at tracking change over months. That makes this a practical body fat percentage calculator for home use.
Quick numbers
Method
US Navy circumference formulaMen measure
height, neck, waist at navelWomen measure
height, neck, narrowest waist, widest hipsTypical error
± 3 to 4 percentage pointsAverage range
men 18 to 24 percent, women 25 to 31 percent
How to measure for the body fat calculator
- Stand straight, relaxed, feet together. Measure in the morning before eating.
- Neck: just below the voice box, tape sloping slightly down to the front.
- Waist, men: around the belly at the navel, at the end of a normal breath out.
- Waist, women: at the narrowest point, usually a little above the navel.
- Hips, women: around the widest part of the buttocks.
- Measure each site twice and use the average. Keep the tape level and snug, not digging in.
Write the numbers down with the date. A change of 1 cm at the waist is worth more than a change of 1 kg on the scale.
Body fat percentage ranges for men and women
| Category | Women | Men |
|---|---|---|
| Essential fat | 10 to 13 percent | 2 to 5 percent |
| Athletes | 14 to 20 percent | 6 to 13 percent |
| Fitness | 21 to 24 percent | 14 to 17 percent |
| Average | 25 to 31 percent | 18 to 24 percent |
| Obese | 32 percent and above | 25 percent and above |
Women need more essential fat than men for hormones and childbearing, which is why every row sits higher. An ideal body fat percentage for most adults is somewhere in the fitness or average rows; athlete levels are hard to hold and not needed for health.
Going too low is a risk of its own. Women under about 15 percent often lose their periods, and very lean men can feel cold, tired and weak.
Fat mass and lean mass
Body fat percentage times weight gives fat mass. A 75 kg man at 20 percent carries 15 kg of fat and 60 kg of lean mass, which is muscle, bone, organs and water. Lean mass is what drives resting energy use, so it feeds straight into the Katch McArdle formula on the BMR calculator.
When you diet, try to keep lean mass steady. Eating enough protein and lifting weights does most of that work; the protein calculator gives a daily gram target.
Body fat percentage calculator using height and weight only
If you have no tape, a rough estimate comes from BMI. One common equation for adults is: body fat % = 1.20 × BMI + 0.23 × age − 10.8 × sex − 5.4, where sex is 1 for men and 0 for women. For a 30 year old man with BMI 24, that gives about 19.5 percent.
It is far less accurate than tape measures because it cannot tell muscle from fat. Use it only as a first guess, and see the BMI calculator for the BMI itself.
How accurate is each body fat method
| Method | How it works | Usual accuracy |
|---|---|---|
| DEXA scan | Low dose X-ray of the whole body | Within about 1 to 2 points |
| Skinfold caliper | Pinches at 3 to 7 sites | 3 to 4 points with a trained tester |
| Navy tape method | Neck, waist, hip and height | 3 to 4 points |
| Bioimpedance scale | Weak current through the feet or hands | 4 to 8 points, changes with water |
| BMI equation | Height, weight, age, sex | 5 or more points |
Pick one method and stick to it. Trends over 8 to 12 weeks matter far more than any single reading.
Body fat in Indian adults
At the same BMI, South Asians tend to carry more body fat and more of it inside the abdomen than Europeans. That is the reason Indian BMI cut-offs are lower, as explained on the BMI calculator India page. A body fat check helps here: someone at BMI 23 with 28 percent fat as a man needs a different plan from a muscular man at BMI 27.
Waist size is the simplest red flag. Indian doctors flag waists over 90 cm in men and 80 cm in women.
Lowering body fat safely
- Aim for a fat loss of 0.5 to 1 percent of body weight a week. The calorie deficit page sets a matching daily target.
- Lift weights two to four times a week to keep muscle.
- Walk daily. Steps add up; see what 10,000 steps burn.
- Sleep 7 to 9 hours. Short sleep raises hunger hormones.
- Crunches strengthen the stomach muscles but do not pick where fat comes off; that happens across the whole body.
If body fat or weight changes fast without effort, or you have a heart, kidney or hormone condition, get a check from a physician before a strict plan.
Frequently asked questions
What is a healthy body fat percentage?
For most women 21 to 31 percent and for most men 14 to 24 percent. Lower is not always better; essential fat is about 10 to 13 percent for women and 2 to 5 percent for men.
How accurate is the navy body fat calculator?
Usually within 3 to 4 percentage points of a DEXA scan when you measure carefully. It is best for tracking change in the same person over time.
Can I calculate body fat from height and weight?
Only roughly, with a BMI based equation. A tape measure at the neck and waist, and hips for women, gives a much better estimate.
What is the most accurate body fat calculator?
Lab methods such as DEXA are the most accurate. For home use, the navy tape formula done carefully is the best free option.
Is body fat percentage different for women?
Yes. Women carry more essential fat, so every healthy range is about 7 to 10 points higher than for men.
How often should I check body fat?
Every two to four weeks is enough. Daily checks mostly measure water changes and can be discouraging.
Sources
- US Navy body composition method
- American Council on Exercise body fat categories