Body Fat Calculator
Estimate your body fat percentage from body measurements.
Measurements (US Navy Method)
Measure neck at narrowest point, waist at navel. Stand relaxed.
Enter your measurements to calculate body fat
ACSM Body Fat Classification
Men
| < 6% | Essential fat |
| 6–13% | Athletic |
| 14–17% | Fitness |
| 18–24% | Average |
| = 25% | Obese |
Women
| < 14% | Essential fat |
| 14–20% | Athletic |
| 21–24% | Fitness |
| 25–31% | Average |
| = 32% | Obese |
Method note: The US Navy circumference method is an estimate (±3–4%). Measure at the correct anatomical sites for best accuracy. DEXA scan remains the clinical gold standard.
Estimate your body fat percentage using the US Navy circumference method — no equipment needed beyond a tape measure. Enter height, neck, and waist measurements (plus hips for women) to get body fat %, fat mass, and lean mass.
Key Features
US Navy method
Uses the validated US Navy body circumference formula, one of the most practical field methods available without specialist equipment.
Fat mass and lean mass
If you enter your body weight, the calculator also shows your estimated fat mass and lean (muscle + bone) mass in kg.
ACSM classification table
ACSM body composition categories (Essential, Athletic, Fitness, Average, Obese) for both men and women are shown with your category highlighted.
Color-coded gauge
A gradient gauge bar shows where your body fat percentage falls across all fitness categories.
How to Use
- 1Select your unit system and biological sex.
- 2Enter your height, neck circumference, and waist circumference (at navel).
- 3For women, also enter hip circumference at the widest point.
- 4Optionally enter your body weight to see fat mass and lean mass.