Body Fat Calculator
Estimate your body fat percentage accurately using the U.S. Navy Method. Enter your body measurements to calculate fat mass, lean mass, and health category.
Tape Measurements
Measure at the navel.
How this Body Fat Calculator works
This calculator estimates your body composition using the U.S. Navy Method. This widely used formula calculates body density based on the circumference of specific body parts relative to your height.
It is a convenient alternative to expensive methods like DEXA scans or hydrostatic weighing, requiring only a standard tape measure.
How to Measure Correctly
For the most accurate results, follow these measurement guidelines:
- Neck: Measure below the larynx (Adam's apple) sloping slightly downward to the front. Keep the tape flat.
- Waist (Men): Measure at the navel level.
- Waist (Women): Measure at the narrowest point of the waist, usually just above the navel.
- Hips (Women only): Measure at the widest point of the hips/buttocks.
Understanding Body Fat Percentage
Body fat percentage is the total mass of fat divided by total body mass. It is a better indicator of health and fitness than BMI because it distinguishes between muscle and fat.
- Essential Fat: The minimum amount of fat necessary for basic physical and physiological health.
- Lean Body Mass: The weight of everything in your body except fat (bones, organs, muscles, water).
Limitations
While the Navy Method is accurate for the general population (usually within 3-4%), it can be less precise for:
- Bodybuilders: May overestimate fat due to large neck/waist ratios not fitting standard models perfectly.
- Elderly: Changes in skin elasticity and density can affect tape measurements.
If you are tracking progress, consistency is key. Measure yourself at the same time of day under the same conditions each week.
? Frequently Asked Questions
Yes, for most people it is considered one of the most accurate estimation methods available without clinical equipment, typically within 3-4% of hydrostatic weighing results.
The formula uses the neck measurement to estimate the proportion of upper body fat and frame size, helping to separate subcutaneous fat from internal visceral fat estimates.
For men, 14-17% is considered 'Fitness' level. For women, 21-24% is the equivalent fitness range. Athletes often maintain lower percentages.
The Navy formula itself relies on measurements, but your categorization (ideal range) shifts slightly with age. Older adults naturally hold slightly more visceral fat.