BMI is a useful screening tool, but body fat percentage gives you a much more accurate picture of your body composition. Two people with the same BMI can have very different body fat levels.
What Is Body Fat Percentage?
Body fat percentage is the proportion of your total weight that comes from fat tissue. The remaining weight comes from muscle, bone, organs, and water.
Unlike BMI, body fat percentage directly measures body composition, making it a better indicator of health and fitness.
How to Measure Body Fat
US Navy Method
The US Navy method uses circumference measurements to estimate body fat. It’s one of the most accessible and reasonably accurate methods available without specialized equipment.
For men, it uses: height, neck circumference, and waist circumference For women, it adds: hip circumference
Our body fat calculator implements this method instantly. You just need a tape measure.
Other Measurement Methods
| Method | Accuracy | Cost | Accessibility |
|---|---|---|---|
| US Navy method | Good | Free | Easy |
| BMI-based estimate | Fair | Free | Easy |
| Calipers (skinfold) | Good | Low | Moderate |
| Bioelectrical impedance | Fair | Low-Moderate | Easy (home scales) |
| DEXA scan | Excellent | High | Clinical |
| Hydrostatic weighing | Excellent | High | Clinical |
Healthy Body Fat Ranges
For Men
| Age | Essential | Athlete | Fit | Average | Obese |
|---|---|---|---|---|---|
| 20-29 | 4-8% | 8-13% | 13-17% | 17-24% | 24%+ |
| 30-39 | 4-8% | 8-14% | 14-18% | 18-25% | 25%+ |
| 40-49 | 4-8% | 9-15% | 15-19% | 19-26% | 26%+ |
| 50-59 | 4-8% | 10-16% | 16-20% | 20-27% | 27%+ |
For Women
| Age | Essential | Athlete | Fit | Average | Obese |
|---|---|---|---|---|---|
| 20-29 | 10-13% | 13-20% | 20-24% | 24-30% | 30%+ |
| 30-39 | 10-13% | 14-21% | 21-25% | 25-31% | 31%+ |
| 40-49 | 10-13% | 15-22% | 22-26% | 26-32% | 32%+ |
| 50-59 | 10-13% | 16-23% | 23-27% | 27-33% | 33%+ |
Women naturally have higher essential body fat than men due to reproductive functions.
Body Fat vs BMI
BMI can misclassify muscular individuals as overweight or obese. Body fat percentage doesn’t have this problem because it directly measures fat mass.
For example, an athlete might have a BMI of 28 (overweight) but a body fat percentage of 12% (athlete range). Our calculator includes both the US Navy method and a BMI-based estimate so you can compare.
How to Lower Body Fat
- Calorie deficit — Use our calorie calculator to find the right intake
- Strength training — Preserves muscle during fat loss
- Adequate protein — 1.6-2.2 g per kg of body weight
- Consistent sleep — Poor sleep increases cortisol, which promotes fat storage
- Track trends, not daily — Body fat measurements fluctuate; track weekly trends
Summary
Body fat percentage gives you a clearer picture of your health than weight or BMI alone. Use our body fat calculator to estimate your body fat using the US Navy method, and track changes over time as you improve your fitness.