Body Fat Percentage & BMI Calculator (Navy Method)
Calculate Body Fat Percentage and BMI using the US Navy Seal formula. Features a visual health gauge, age-adjusted insights, and accurate anthropometric analysis.
About
Monitoring body composition provides a clearer picture of health than weight alone. While Body Mass Index is a useful general screen it often misclassifies muscular individuals as overweight. Body Fat Percentage distinguishes between lean mass and adipose tissue offering a more actionable metric for fitness progress.
This tool combines standard BMI calculations with the US Navy Seal method which utilizes circumference measurements to estimate body density. By factoring in neck and waist size (and hips for women) we can mathematically approximate fat tissue volume with high correlation to hydrostatic weighing. The result helps you understand if you fall into essential fat, athlete, fitness, average, or obese categories based on physiological norms.
Formulas
The calculator uses the US Navy circumference method. All measurements are converted to centimeters for the logarithmic calculation.
BMI is calculated using the standard mass-to-height ratio:
Reference Data
| Category | Women (% Fat) | Men (% Fat) | Description |
|---|---|---|---|
| Essential Fat | 10 - 13% | 2 - 5% | Critical for survival |
| Athletes | 14 - 20% | 6 - 13% | High performance |
| Fitness | 21 - 24% | 14 - 17% | Active lifestyle |
| Average | 25 - 31% | 18 - 24% | General population |
| Obese | > 32% | > 25% | Health risk |
| BMI Underweight | < 18.5 | Low body mass | |
| BMI Normal | 18.5 - 24.9 | Standard range | |
| BMI Overweight | 25.0 - 29.9 | Increased risk | |