AIAZHHow To Use
- Select your gender (male or female) for the correct calculation formula.
- Measure and enter your height, neck circumference, and waist circumference.
- If female, also measure and enter your hip circumference.
- Click "Calculate Body Fat" to see your estimated body fat percentage.
- Review your category and use the results to track your fitness progress over time.
Frequently Asked Questions
How accurate is the Navy body fat method?
The US Navy method has an accuracy of about ±2-3% when compared to hydrostatic weighing. It is one of the most accurate circumference-based methods available without specialized equipment.
How do I measure neck circumference correctly?
Measure around the neck just below the larynx (Adam's apple), with the tape measure perpendicular to the neck's long axis. Keep the tape level and snug but not tight against the skin.
What is a healthy body fat percentage?
For men, 10-20% body fat is generally healthy. For women, 18-28% is generally healthy. Athletes typically have lower ranges: 6-13% for men and 14-20% for women.
How does body fat differ from BMI?
BMI estimates body mass relative to height, while body fat percentage directly measures fat tissue. Two people with the same BMI can have very different body fat percentages. Body fat percentage gives a more accurate picture of health and fitness.
Is my measurement data stored or shared?
No. All calculations are performed locally in your browser. Your body measurements never leave your device.
Can I track changes over time?
Yes. Since the calculator works entirely in your browser, you can take measurements at regular intervals and recalculate to track your body composition changes throughout your fitness journey.
US Navy Method
Uses the validated US Navy circumference method which estimates body fat percentage from simple body measurements with high accuracy.
Gender-Specific Calculation
Separate formulas for men and women. Women's calculation includes hip measurement for more accurate results.
100% Private & Secure
Your body measurements never leave your device. All calculations happen locally in your browser with JavaScript.
Free & No Signup
No account required, no email needed. Use the body fat calculator unlimited times for free.
Estimate Body Fat Percentage with the Navy Method
Our free body fat calculator uses the US Navy circumference method to estimate your body fat percentage. This validated technique requires only a tape measure and provides results comparable to more expensive methods like hydrostatic weighing or DEXA scans.
Why Body Fat Percentage Matters More Than Weight
Your body fat percentage is a better indicator of health and fitness than weight alone. Two people weighing the same can have vastly different body compositions. Tracking body fat helps you understand whether your weight changes come from fat loss or muscle gain.
How to Take Accurate Body Measurements
For consistent results, take measurements at the same time of day, ideally in the morning before eating or exercising. Use a flexible tape measure and ensure it is level and snug but not compressing the skin. Record measurements to the nearest 0.5 cm.
Body Fat Ranges for Men and Women
Essential fat levels are 2-5% for men and 10-13% for women. Athletes range from 6-13% (men) and 14-20% (women). Fitness ranges are 14-17% (men) and 21-24% (women). Acceptable ranges are 18-24% (men) and 25-31% (women). Above these is considered obese.