A body fat percentage calculator estimates fat mass versus lean mass. Our calculator uses the U.S. Navy circumference method—a validated field test requiring only a tape measure.
Body fat percentage categories
| Category | Men | Women |
|---|---|---|
| Essential fat | 3–5% | 12–15% |
| Athlete | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average/acceptable | 18–24% | 25–31% |
| Obese | > 25% | > 32% |
How the U.S. Navy body fat calculator works
Formula requires measurements in cm:
| Sex | Formula |
|---|---|
| Men | 495 ÷ (1.0324 - 0.19077×log(waist-neck) + 0.15456×log(height)) - 450 |
| Women | 495 ÷ (1.29579 - 0.35004×log(waist+hip-neck) + 0.221×log(height)) - 450 |
Our body fat calculator handles all math instantly.
Calculating body fat from body composition
Alternative formula:
Body fat % = (fat mass ÷ total weight) × 100
If you know lean mass, use our lean body mass calculator to find the difference.
Body fat methods ranked by accuracy
| Method | Accuracy | Cost | Convenience |
|---|---|---|---|
| DEXA/DEXA scan | Gold standard | $50–150 | Clinic visit required |
| U.S. Navy method | ~±3–5% | Free | Easy at home |
| Calipers (3-site) | ~±3–7% | $20–100 | Requires training |
| Smart scales | ~±5–10% | $50–200 | Convenient but variable |
Why body fat matters for calories
Body fat affects maintenance calories:
- Lower body fat = higher metabolic rate (less weight, more muscle)
- Higher body fat = lower BMR (but not proportionally as much as expected)
- Use TDEE calculator with current weight
Tracking body fat changes
Measure every 2–4 weeks under consistent conditions:
- Same time of day (morning best)
- Similar hydration status
- Same tape measure tension
- Record measurements precisely
Sources and further reading
These independent, authoritative sources inform the methods used on this page.