Body Fat Calculator
BMI cannot tell muscle from fat. This estimate adds your age and sex to give a closer reading of body composition.
Enter your details to estimate your body fat percentage.
- BMI (kg/m²)—
- BMI category—
This is a BMI-based estimate, not a measurement. Calipers, a scale with bioelectrical impedance, or a DEXA scan will be more accurate.
Why BMI is not the same as body fat
BMI compares your weight with your height. Body fat percentage tells you what share of that weight is fat. Two people can share a BMI of 27 while one is lean and muscular and the other carries 35 percent body fat. The number on the scale cannot tell the difference, which is why athletes are so often labeled overweight by BMI alone.
How this estimate is calculated
The formula behind this tool was published by researchers led by Anja Deurenberg as a way to approximate body fat from BMI without equipment. It adjusts the BMI figure for age and sex, because for the same BMI older adults and women tend to carry a higher proportion of fat. It is a good approximation for the general population and a poor one for bodybuilders, endurance athletes and anyone at the extremes.
Typical body fat ranges
| Category | Men | Women |
|---|---|---|
| Essential fat | 2 – 5% | 10 – 13% |
| Athletic | 6 – 13% | 14 – 20% |
| Fitness | 14 – 17% | 21 – 24% |
| Average | 18 – 24% | 25 – 31% |
| Obese | 25% and above | 32% and above |
Women carry more essential fat than men for biological reasons, so the healthy bands are roughly seven percentage points higher. A body fat reading that would be high for a man can be perfectly normal for a woman.
More accurate ways to measure body fat
- DEXA scan: the clinical standard, usually a few hundred dollars.
- Hydrostatic weighing: accurate but only offered at research facilities.
- Air displacement plethysmography: similar accuracy to underwater weighing.
- Skinfold calipers: inexpensive and reliable in trained hands.
- Bioelectrical impedance scales: convenient, but hydration shifts the reading.
The best measurement is the one you can repeat. A bathroom scale that reads 22 percent when the true figure is 24 percent is still useful if it reads 20 percent after three months of consistent work, because the trend is real even when the absolute number is not.
What moves body fat, in order of impact
Weight training protects and builds muscle while you lose fat. Protein at every meal supports that muscle and keeps you full. Sleep matters more than most people expect, because short sleep raises appetite hormones and lowers training quality. Alcohol and liquid sugar add calories that do not register as food. And consistency over months beats intensity over weeks every time.