Body Fat Calculator
Estimate body fat percentage using U.S. Navy method. Neck, waist, height, weight measurements.
Free · Runs in your browser · No signup
Uses the US Navy circumference formula. Estimate only — not medical advice.
Examples to try
US Navy style estimate
Tape-measure method using height, neck, and waist (hip for women). Typical error band is a few percentage points.
How to Use
Enter your values in the fields above and click Calculate to get instant results. Calculations run in your browser. Results are estimates for personal planning only.
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US Navy Body Fat Formula
CalcSolver estimates body fat percentage using the US Navy method — a validated tape-measure formula that requires only height, neck, and waist measurements.
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
All measurements in centimeters. The Navy method has a ±3–4% margin of error, making it practical for home tracking.
Body Fat Category Standards
Men — Essential: 2–5% · Athletes: 6–13% · Fitness: 14–17% · Average: 18–24% · Obese: 25%+
Women — Essential: 10–13% · Athletes: 14–20% · Fitness: 21–24% · Average: 25–31% · Obese: 32%+
Values below essential-fat thresholds risk hormonal disruption. Track trends weekly rather than single readings — daily fluctuation of 1–2% is normal.
Measuring Body Fat Percentage
Body fat percentage is a more precise health indicator than BMI alone. CalcSolver's body fat calculator uses the US Navy method — a validated formula based on waist, neck, and height measurements — to estimate your body fat percentage without specialized equipment.
Healthy body fat ranges differ by gender: men: 10-22% (essential fat minimum is 2-5%), women: 20-32% (essential fat minimum is 10-13%). A man with 15% body fat at 175cm and 75kg is in the "fitness" range, while the same measurements at 25% body fat would be considered "acceptable" but approaching overweight.
The US Navy method is practical but has a 3-4% margin of error. For more precise measurement, consider DEXA scans or hydrostatic weighing. Track trends rather than single measurements — body fat changes gradually, and weekly fluctuations are normal. Use CalcSolver's BMI calculator and ideal weight calculator alongside this tool.
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Frequently Asked Questions
How is body fat percentage estimated?
This calculator uses the U.S. Navy method, which estimates body fat from body measurements (waist, neck, height, and hip for women). It is a practical alternative to expensive lab tests like DEXA scans.
What is a healthy body fat percentage?
For men: essential fat 2-5%, athletes 6-13%, fitness 14-17%, acceptable 18-24%. For women: essential fat 10-13%, athletes 14-20%, fitness 21-24%, acceptable 25-31%.
Why is body fat percentage better than BMI?
BMI does not distinguish between muscle and fat. A muscular person can have an overweight BMI with low body fat. Body fat percentage directly measures the proportion of fat in your body.
How accurate is this method?
The Navy method has an accuracy of about ±3-4% compared to DEXA scans. For most people, it provides a good estimate for tracking trends over time.