How to Use Body Fat Calculator
The Body Fat Calculator estimates your body fat percentage in a few easy steps:
- Choose your unit system — Select Metric (cm) or Imperial (in) at the top of the Body Fat Calculator.
- Select your gender — Male and female calculations use different formulas. Female users will also see a hip circumference field.
- Enter your measurements — Input height, waist circumference (at the navel), and neck circumference. Female users additionally enter hip circumference (at the widest point).
- Read your result — The Body Fat Calculator instantly shows your estimated body fat percentage and a category label.
For the most accurate Body Fat Calculator result, take measurements in the morning before eating. Use a flexible, inelastic tape measure and keep it parallel to the floor.
Formula & Theory — Body Fat Calculator
The Body Fat Calculator implements the U.S. Navy circumference method, one of the most widely used non-invasive body fat estimation formulas:
Male formula:
Body Fat % = 86.010 × log10(Waist − Neck) − 70.041 × log10(Height) + 36.76
Female formula:
Body Fat % = 163.205 × log10(Waist + Hip − Neck) − 97.684 × log10(Height) − 78.387
All circumferences are in centimeters and height is in centimeters.
| Symbol | Meaning |
|---|---|
| Waist | Waist circumference measured at the navel |
| Neck | Neck circumference just below the larynx |
| Hip | Hip circumference at the widest point (female only) |
| Height | Standing height |
The Body Fat Calculator uses logarithmic regression to relate body circumferences to overall adiposity. The U.S. Navy developed this formula to enable rapid field assessments without specialised equipment.
Body Fat Category Reference
| Category | Men | Women |
|---|---|---|
| Essential fat | < 6% | < 14% |
| Athlete | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | ≥ 25% | ≥ 32% |
Use Cases for Body Fat Calculator
The Body Fat Calculator is useful across many health and fitness contexts:
- Fitness goal setting — Athletes and gym-goers use the Body Fat Calculator to establish a baseline and track changes in body composition over weeks and months.
- Weight management — Individuals on diet programs use the Body Fat Calculator alongside scale weight to determine whether they are losing fat or muscle.
- Health screening — Clinicians and health coaches use the Body Fat Calculator as a quick preliminary screening tool before ordering more precise tests.
- Sports performance — Coaches in weight-class sports (wrestling, boxing, rowing) use the Body Fat Calculator to monitor athletes' body composition during cutting phases.
- Educational use — Exercise science and nutrition students use the Body Fat Calculator to practise applying the U.S. Navy formula and understand how body circumferences relate to adiposity.
Keep in mind that the Body Fat Calculator provides an estimate. Results can vary based on measurement technique, body shape, and individual physiology. This tool is for reference only and does not replace professional medical or fitness assessments.