What is Body Fat Percentage?
Body fat percentage is the total mass of fat divided by total body mass, multiplied by 100. Body fat includes **essential body fat** (necessary for life and reproductive functions) and **storage body fat** (tissue that protects internal organs and stores energy).
This calculator uses the **U.S. Navy circumference method**, which estimates body fat by measuring specific points on the body. While DEXA scans are the gold standard, the Navy formula is widely considered the most accurate non-clinical estimation tool available.
The U.S. Navy Body Fat Formula
Developed by the U.S. Navy Health Research Center, this formula uses log-based equations to predict body density based on the difference between your neck and abdominal measurements.
For Men (Metric)
495 / (1.0324 - 0.19077 * log10(waist - neck) + 0.15456 * log10(height)) - 450For Women (Metric)
495 / (1.29579 - 0.35004 * log10(waist + hip - neck) + 0.221 * log10(height)) - 450Why Body Fat Matters More Than Weight
Two people can weigh exactly the same but have completely different health profiles. A 90kg athlete with 10% body fat is metabolically healthier than a 90kg sedentary individual with 35% body fat. High body fat, particularly **visceral fat** stored around organs, increases the risk of Type 2 diabetes and heart disease.
Measurement Limitations
The Navy Method is an estimation tool, not a clinical measurement. It can have a margin of error of +/- 3% compared to DEXA scans. Factors like skin thickness, hydration levels, and exactly where you place the measuring tape can influence the result. For high-stakes medical tracking, clinical imaging is recommended.
↗ Holistic Metrics
Pair your body fat percentage with these tools for a better overview:
| Category | Men (%) | Women (%) |
|---|---|---|
| Essential Fat | 2 - 5% | 10 - 13% |
| Athletes | 6 - 13% | 14 - 20% |
| Fitness | 14 - 17% | 21 - 24% |
| Average | 18 - 24% | 25 - 31% |
| Obese | 25%+ | 32%+ |
Frequently Asked Questions
Scientific Sources
Clinical Reference: US Navy Health Research Center | ACSM Guidelines
Editorial Status
Last Updated: January 2026 | Reviewed by Fitness Professionals