How the US Navy Body Fat Method Works
The US Navy body fat formula estimates body fat percentage from circumference measurements. It was developed by the Naval Health Research Center and is widely used because it needs no special equipment — just a flexible tape measure.
What to measure:
- Men: height, neck (below the Adam's apple), and waist (at the navel)
- Women: height, neck, waist (narrowest point), and hips (widest point)
Measure in inches, standing relaxed — don't suck in your stomach. Take each measurement twice and use the average for best accuracy.
Body Fat Percentage Categories
| 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%+ |
How Accurate Is It?
The Navy method is typically accurate within 3–4% of clinical methods like DEXA scans for most people. It is less reliable for very muscular individuals (it can overestimate) and is not designed for children or pregnant women. For tracking fitness progress over time, consistency of measurement matters more than absolute precision — measure the same way each time.
Body Fat vs. BMI
BMI only uses height and weight, so it can't distinguish muscle from fat. Two people with the same BMI can have very different body compositions. Body fat percentage is the more meaningful number for fitness — pair this tool with our calorie calculator to plan nutrition around your goals.
Related calculators: BMI Calculator, Calorie Calculator.
Frequently Asked Questions
Is this body fat calculator accurate?
It uses the validated US Navy circumference formula, typically within 3–4% of lab methods. Measure carefully and consistently for the best results.
Do I need calipers?
No. Unlike skinfold methods, the Navy formula only needs a tape measure.
Why do women measure hips too?
The women's formula includes hip circumference because fat distribution differs by sex — it improves the estimate.
Can athletes use this?
Yes, but very muscular people may get an overestimate since the formula can't distinguish muscle from fat around the waist and neck.
Last updated: 2026 | Uses the US Navy circumference formula (Naval Health Research Center).