This body fat calculator estimates your body fat percentage using either the quick BMI method or the advanced U.S. Navy method. It provides fat percentage, fat mass, lean body mass, and classification into fitness categories.
- BMI method: Uses age, gender, height, and weight for a fast estimate.
- U.S. Navy method: Uses waist, neck, hips (for women), and height for more accuracy.
- Results include: Body fat %, lean body mass, fat mass, and body fat category.
- Fitness categories: Essential fat, athletes, fitness, average, obese.
- Dual modes: Choose Simple or Advanced for flexibility.
How to use: Select Simple mode for a quick BMI-based estimate. Use Advanced mode if you know your waist, neck, and hip measurements for a more precise calculation. Results update instantly with body fat percentage and category.
Common searches: body fat calculator, Navy body fat calculator, body fat percentage by BMI, body composition calculator, lean body mass calculator.
Body Fat Calculator
Estimate your body fat percentage using either the quick BMI method or the advanced U.S. Navy method.
How the body fat calculator works
The body fat calculator estimates your fat percentage using either a BMI-based formula or the U.S. Navy circumference method. Both methods give an approximation of body composition without medical scans.
- BMI method: Uses the equation 1.20 × BMI + 0.23 × age − (10.8 × gender) − 5.4.
- U.S. Navy method: Uses waist, neck, height (and hips for women) with a logarithmic formula.
Body fat percentage categories
Body fat is classified into ranges that reflect health, fitness, and performance levels. These categories differ between men and women due to natural physiology.
| 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+ |
Worked examples
- BMI method: A 30-year-old male, 180 cm tall, 80 kg → BMI = 24.7 → Body fat ≈ 19%.
- Navy method (male): Height 175 cm, neck 38 cm, waist 85 cm → Body fat ≈ 18%.
- Navy method (female): Height 165 cm, neck 34 cm, waist 72 cm, hips 95 cm → Body fat ≈ 25%.
Why body fat percentage matters
Body fat percentage is a better indicator of health and fitness than weight alone. It distinguishes fat mass from lean muscle, helping track progress, set training goals, and assess risk for conditions such as heart disease and diabetes.
Limitations of body fat calculators
These calculators provide estimates, not medical-grade results. Accuracy can vary depending on body type, measurement technique, and formula used. For clinical accuracy, methods like DEXA scans or hydrostatic weighing are recommended.
Body Fat Calculator FAQs
Body fat percentage is the proportion of fat compared to total body weight. It matters because it reflects overall health, fitness level, and risk for conditions such as heart disease, diabetes, and metabolic syndrome.
The body fat calculator provides an estimate. The U.S. Navy method is generally more accurate than BMI-based estimates, but clinical methods like DEXA scans and hydrostatic weighing are more precise.
For men, the average range is 18–24%. For women, it is 25–31%. Athletes typically fall in lower ranges, while essential fat levels are the minimum required for survival.
Healthy body fat depends on age and gender. For men, 14–24% is generally considered healthy. For women, 21–31% is healthy. Athletes may have lower percentages, while obese categories begin above 25% for men and 32% for women.
You can estimate body fat using calculators that require only height, weight, and measurements such as waist, neck, and hips. This gives a reasonable approximation without advanced equipment.
Yes. BMI only considers height and weight, so muscular individuals may appear overweight. Body fat percentage distinguishes between fat mass and lean muscle, making it more reliable for assessing fitness.
No. Extremely low body fat can cause hormonal issues, fatigue, and impaired immunity. Essential fat is required for survival: 2–5% in men and 10–13% in women.