Based on the US Navy Method.
Body fat percentage (BF%) is more meaningful than body weight alone. Two people with the same weight can have completely different fitness levels. Our Body Fat Calculator uses the proven US Navy Method to estimate your body fat percentage from simple body measurements.
Men:
BF% = 495 / (1.0324 - 0.19077 × log(Waist - Neck) + 0.15456 × log(Height)) - 450
Women:
BF% = 495 / (1.29579 - 0.35004 × log(Waist + Hip - Neck) + 0.22100 × log(Height)) - 450
Accuracy: ±3-4% compared to DEXA scans
Men:
• Essential: 2-5% (vital for survival)
• Athletes: 6-13%
• Fitness: 14-17%
• Average: 18-24%
• Overweight: >25%
Women:
• Essential: 10-13%
• Athletes: 14-20%
• Fitness: 21-24%
• Average: 25-31%
• Overweight: >32%
Muscle weighs more than fat! A muscular person can be "overweight" by BMI but have low body fat. Conversely, someone with "normal weight" can have high body fat ("skinny fat"). BF% shows actual body composition.
It's ±3-4% accurate compared to DEXA scans. For home use, it's one of the best methods. Important: Always measure at the same time (morning, fasted) and use correct measurement points.
For men: 10-20% is healthy, below 10% is mainly for competitive athletes. For women: 18-28% is healthy. Below 15% in women can cause hormonal and menstrual issues. Very low values aren't automatically better!
DEXA scan (most accurate, ~$50-100), Caliper/skinfold measurement (cheap, requires practice), Bio-impedance scales (inaccurate but shows trends), Hydrostatic weighing (lab), Bod Pod (lab).
Pro Tip: Always measure at the same time (morning after waking) and under the same conditions. Track the trend over weeks, not daily fluctuations!