Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy circumference method — just a tape measure and a few simple measurements.
Enter Your Measurements
This estimate uses the U.S. Navy circumference method. It’s a convenient at-home method but is less precise than clinical tools like DEXA scans or hydrostatic weighing.
How Body Fat Is Calculated
This calculator uses the U.S. Navy method, which estimates body fat percentage from a few circumference measurements rather than skinfold calipers or scans. All measurements are converted to inches internally and height and circumferences are used in the log-based formula below.
Lean body mass and fat mass are then derived from your total weight and the calculated body fat percentage.
| 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%+ | 32%+ |
Frequently Asked Questions
How accurate is the U.S. Navy method?
It’s generally accurate within about 3–4% of more precise methods like DEXA scans for most people, which makes it a solid free option for tracking trends at home. It can be less reliable for very lean or very heavy individuals.
Why does the formula need a hip measurement for women but not men?
Fat distribution patterns differ by gender — women tend to store more fat around the hips, so the Navy method’s female formula includes hip circumference to account for this and improve accuracy.
How should I measure my waist and neck correctly?
Measure your neck just below the larynx (Adam’s apple), keeping the tape slightly angled downward at the front. Measure your waist at the navel while standing relaxed, not sucking in. Keep the tape snug against the skin without compressing it.
What’s the difference between body fat percentage and BMI?
BMI only looks at weight relative to height and can’t tell fat from muscle. Body fat percentage measures how much of your total weight is actually fat, which gives a more accurate picture of body composition, especially for muscular or very lean individuals.