Body Fat Calculator

📋 How to Use This Calculator

1. 1Select your gender, then enter your height, waist circumference, and neck circumference in centimeters.
2. 2For females, also enter your hip measurement — the Navy formula requires this additional data point.
3. 3Click 'Calculate Body Fat' to see your estimated percentage and fitness category.

💡 How the U.S. Navy body-fat method works

The Navy circumference formula (Hodgdon & Beckett, 1984) estimates body density from where fat actually accumulates — the waist and neck for men, plus hips for women — and then converts density to fat percentage. For men: 495 / (1.0324 − 0.19077·log10(waist − neck) + 0.15456·log10(height)) − 450. For women, waist + hip replace waist in the log term.

Because it uses tape measurements rather than height/weight, it captures composition that BMI misses — a muscular 85 kg athlete and a sedentary 85 kg office worker can share the same BMI but differ by 15% body fat. Accuracy is within ±3–4% of a DEXA scan when you measure at the navel, mid-neck, and widest hip point, standing relaxed. Healthy ranges: men 10–20%, women 18–28%; athletic men 6–13%, athletic women 14–20%.

🏆 Why Use Our Tool?

• ✓2026 Accuracy — Built with the latest formulas and standards to give you precise, up-to-date results.
• ✓Privacy First — No data is stored or transmitted. All calculations happen right in your browser.
• ✓Fast Browser-Based Results — No sign-ups, no downloads. Just enter your values and get instant answers.

Measure at the same time of day (morning, before eating) and re-check monthly — trend direction matters more than any single reading.