How to Use This Calculator
- Select biological sex: The US Navy method uses different logarithmic formulas for men and women.
- Take tape measurements: Measure neck circumference just below the larynx, and waist horizontally at the navel.
- Women measure hips: For females, measure around the widest part of the buttocks and hips.
Formula and Calculation Steps
US Navy Formulas:
Men: % Body Fat = 495 ÷ [ 1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height) ] − 450
Women: % Body Fat = 495 ÷ [ 1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height) ] − 450Worked Examples and Reference Table
| Category | Women (% Body Fat) | Men (% Body Fat) |
|---|---|---|
| Essential Fat | 10% – 13% | 2% – 5% |
| Athletes | 14% – 20% | 6% – 13% |
| Fitness | 21% – 24% | 14% – 17% |
| Average | 25% – 31% | 18% – 24% |
| Obese | 32%+ | 25%+ |
Frequently Asked Questions
How accurate is the US Navy Body Fat method?
The US Navy circumference method is accurate within 3% to 4% for the majority of adults compared to dual-energy X-ray absorptiometry (DEXA) scans, provided measurements are taken consistently.
Where should I measure waist and neck circumferences?
Measure your neck horizontally just below the Adam’s apple. Measure waist horizontally at the narrowest point for women or at the level of the navel for men.
Why do women require a hip measurement?
Biological females naturally store higher proportions of essential adipose tissue in the lower body, including hips and thighs. Adding hip circumference ensures accurate body fat estimation.
What is considered an ideal body fat percentage?
For men, a healthy fitness range is 14% to 17%, while athletes often range from 6% to 13%. For women, fitness ranges from 21% to 24%, while athletes typically measure 14% to 20%.
Can you have too little body fat?
Yes. Essential body fat (2% to 5% for men, 10% to 13% for women) is necessary for hormonal regulation, neurological insulation, organ cushioning, and temperature control.