Body Fat Calculator
What is body fat percentage?
Body fat percentage is the share of your weight that is fat. Two people at the same weight can look very different, so it tells you more than weight alone. The rest — lean mass — is muscle, bone, and water, and it’s the basis for protein and calorie targets.
The US Navy tape method
The Navy method estimates body fat from height and neck, waist (and hip for women) measurements. No calipers or devices — just a tape — and it’s fairly consistent when measured carefully. Prefer not to use a tape? Switch to the BMI-based estimate (a bit less accurate).
Body fat categories (ACE)
| Category | Female | Male |
|---|---|---|
| Essential | 10–13% | 2–5% |
| Athletes | 14–20% | 6–13% |
| Fitness | 21–24% | 14–17% |
| Average | 25–31% | 18–24% |
| Obese | 32%+ | 25%+ |
Source: American Council on Exercise (ACE)
How accurate is it?
As a tape-based estimate, it’s typically within ±3–4% of lab methods like DEXA or hydrostatic weighing. Use it to track your trend with the same method over time rather than as an exact number.
FAQ
What’s a healthy body fat percentage?
Roughly 14–24% for men and 21–31% for women is considered healthy. Athletes run lower; going too low can harm hormones and immunity.
How do I lower body fat?
A small calorie deficit, enough protein, and strength training. Keeping muscle while losing fat is what lowers your percentage, even at the same weight.
How should I measure for accuracy?
Keep the tape level and snug but not tight. Measuring at the same time of day (usually morning, fasted) and the same spots makes tracking reliable.
Why does my smart scale show a different number?
Smart scales use bioelectrical impedance, which swings with hydration. Different methods give different numbers — that’s normal; pick one and stay consistent.