How Body Fat Is Calculated
This calculator uses the US Navy method, which estimates body fat based on circumference measurements. It was developed by Hodgdon and Beckett at the Naval Health Research Center.
Men: BF% = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
Women: BF% = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
How to Measure
- Neck: Measure just below the larynx (Adam's apple), tape sloping slightly downward to the front
- Waist: Men: at navel level. Women: at the narrowest point
- Hips (women only): At the widest point of the buttocks
Healthy Body Fat Ranges
- Essential fat: Men 2-5%, Women 10-13% (minimum for survival)
- Athletes: Men 6-13%, Women 14-20%
- Fitness: Men 14-17%, Women 21-24%
- Average: Men 18-24%, Women 25-31%
- Obese: Men 25%+, Women 32%+
Frequently Asked Questions
How accurate is the Navy method? The US Navy method has a typical accuracy of ±3-4%. For more precise measurements, consider DEXA scans, hydrostatic weighing, or Bod Pod.
Why is body fat better than BMI? BMI doesn't distinguish between muscle and fat. A muscular person may have a high BMI but low body fat. Body fat percentage gives a more complete picture of health.
How can I lower my body fat? Combine strength training (preserves muscle), cardio (burns calories), and a moderate caloric deficit (500 cal/day). Aim for 0.5-1% body fat reduction per month.