About the Body Fat Calculator
A body fat calculator estimates the percentage of your weight that is fat. This tool uses the U.S. Navy circumference method, which needs only a tape measure: your height, neck and waist (plus hip for women). It returns your body-fat percentage, a fitness category, and — if you add your weight — your fat mass and lean mass.
How Body Fat Calculator works
U.S. Navy formula (measurements in cm):
Men: %BF = 495 ÷ (1.0324 − 0.19077·log₁₀(waist − neck) + 0.15456·log₁₀(height)) − 450.
Women: %BF = 495 ÷ (1.29579 − 0.35004·log₁₀(waist + hip − neck) + 0.22100·log₁₀(height)) − 450.
Common uses
- Estimate body fat % without a scale or calipers
- Track changes over time with simple tape measurements
- See fat mass vs lean mass from your weight
- Check your fitness category
Frequently asked questions
How accurate is the Navy method?
It is reasonably accurate for most people (within a few percent) and far cheaper than DEXA or calipers, but it is still an estimate.
Where do I measure?
Neck below the larynx, waist at the navel (men) or narrowest point (women), and hip at the widest point (women). Keep the tape snug and level.
What is a healthy body fat range?
Roughly 14–24% for men and 21–31% for women is considered average/healthy; athletes are lower.