Body Fat Calculator
Estimate your body fat percentage from a tape measure, using the US Navy method.
Runs in your browser — nothing is sent or saved.
How to calculate body fat with a tape measure
- Choose your sex and pick metric or imperial.
- Enter your height and your neck and waist measurements.
- Women also enter the hip measurement.
- Add your weight to also see fat mass and lean mass.
The US Navy body fat method
This body fat percentage calculator uses the US Navy circumference method, which estimates body-fat percentage from a few tape measurements rather than a scale or scan. For men it uses height, neck, and waist. For women it adds the hips, because fat distribution differs. The formula compares these girths against your height to work out the body fat percentage. It is the same method used in the classic Navy fitness assessment.
How to measure
Use a soft tape and keep it snug without squeezing the skin.
| Measurement | Where |
|---|---|
| Neck | just below the larynx, tape sloping slightly down to the front |
| Waist | at the navel for men, at the narrowest point for women |
| Hips | at the widest point (women only) |
| Height | standing straight, without shoes |
Measure on bare skin or thin clothing, and take each measurement twice to be sure.
Body fat percentage categories
These are the categories from the American Council on Exercise (ACE).
| Description | Women | Men |
|---|---|---|
| Essential fat | 10 to 13% | 2 to 5% |
| Athletes | 14 to 20% | 6 to 13% |
| Fitness | 21 to 24% | 14 to 17% |
| Average | 25 to 31% | 18 to 24% |
| Obese | 32% and above | 25% and above |
Source: American Council on Exercise (ACE) body-fat norms.
How accurate is the tape method
The Navy method is convenient and repeatable, and for most people it lands within a few points of a more precise test like a DEXA scan or hydrostatic weighing. It can be less accurate at the extremes or for very muscular builds, since it only reads circumferences. Consistency matters most: measure the same way each time so the trend is honest, even if the exact number is a little off.
An estimate, not medical advice
Body fat percentage from any tape formula is an estimate, not a medical measurement. Use it to track change over weeks, not to diagnose anything. Speak to a doctor for health decisions.
FAQ
How do I calculate body fat percentage?
Measure your height, neck, and waist, plus hips if you are a woman, and this tool applies the US Navy formula to estimate your body fat percentage. Adding your weight also splits fat mass from lean mass.
What is a healthy body fat percentage?
By the ACE norms, the fitness range is about 21 to 24% for women and 14 to 17% for men, with the average range a little higher. Athletes sit lower.
Is the Navy body fat method accurate?
It is a good estimate, usually within a few points of a body scan, as long as you measure carefully and the same way each time. Very muscular builds can read a little high.
Can I measure body fat without calipers?
Yes. This method needs only a tape measure, which is why it is popular. Calipers and scans are more precise but need equipment or a clinic.
Are my measurements private?
Yes. The calculation runs in your browser and nothing you enter is uploaded or saved.