Body Fat Percentage Calculator
Estimate your body fat using the US Navy circumference method — no special equipment needed. Just a tape measure and three measurements.
Validated Formula
Based on the Hodgdon & Beckett 1984 Naval Health Research Center formula, widely used by the US military and fitness professionals.
Not Medical Advice
Always consult a qualified healthcare provider for personalized health assessments.
What Is Body Fat Percentage?
Your quick reference for understanding body fat
Body fat percentage is the proportion of your total body weight that consists of fat tissue. Unlike BMI, it distinguishes fat from muscle, making it a more precise indicator of body composition for most adults. Our calculator uses the US Navy circumference method — a validated, equipment-free formula requiring only a tape measure.
Quick Answer: The Navy method estimates body fat from waist, neck, and (for women) hip circumferences. Healthy ranges are typically 14–18 % for men and 21–25 % for women (ACE Fitness categories).
Accurate measurements are essential — a 1 cm error in waist circumference can shift the result by roughly 0.5–1 percentage point. Use a flexible, non-stretch tape measure and follow these steps.
Neck circumference
Stand upright and relax. Place the tape measure at the narrowest point of your neck, just below the larynx (Adam's apple). Tilt your chin slightly downward. Keep the tape level all the way around. Record the measurement at the end of a normal exhale.
Waist circumference — men
Stand relaxed with feet together. Place the tape at navel level, horizontally around your abdomen. Do not suck in your stomach. Measure at the end of a normal exhale.
Waist circumference — women
Stand relaxed. Place the tape at the narrowest point of your waist, usually just above the navel. Keep the tape level. Measure at the end of a normal exhale.
Hip circumference (women only)
Stand with feet together. Place the tape at the widest point of your hips and buttocks (typically at the level of the greater trochanter). Keep the tape horizontal. Record the widest reading.
Height
Stand upright without shoes on a flat surface. Measure from the floor to the top of your head. If available, use a wall-mounted stadiometer; otherwise use a tape measure against a wall with a flat book on your head.
Take each measurement twice and use the average. Consistent technique matters more than the tape brand.
The American Council on Exercise (ACE) provides widely-used reference ranges for body fat percentage by sex. These categories are not disease thresholds — they are population-derived benchmarks.
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2–5 % | 10–13 % |
| Athletes | 6–13 % | 14–20 % |
| Fitness | 14–17 % | 21–24 % |
| Average | 18–24 % | 25–31 % |
| Obese | 25 %+ | 32 %+ |
Essential fat is the minimum amount needed for vital physiological functions including hormone regulation and insulation of organs. Dropping below essential fat levels is medically dangerous.
Athletes in this context means regular exercisers with high muscle mass, not exclusively competitive athletes.
The Navy circumference method is convenient and free, but it is a screening estimate — not a laboratory measurement.
Strengths
No special equipment needed. Takes 2–3 minutes. Validated against hydrostatic weighing. Used by the US military for official fitness assessments. Typical error of ±3–4 % compared to DEXA.
Limitations
Assumes typical fat distribution; less accurate for very muscular individuals, pregnant women, or those with unusual proportions. Does not account for ethnicity. Measurement error by the user adds to formula error.
Comparison with other methods:
Medical Disclaimer
This calculator provides an estimate for general wellness awareness only. It is not a diagnostic tool and does not replace clinical assessment. Consult a qualified healthcare provider before making health or fitness decisions based on these results.