Free Body Fat Calculator
Estimate your body fat percentage using the US Navy method. Everything runs in your browser.
The Body Fat Calculator estimates your body fat percentage using the US Navy method from a few simple measurements. Everything is computed in your browser, so your measurements never leave your device.
What is the Body Fat Calculator?
A Body Fat Calculator estimates your body fat percentage using circumference measurements rather than more complex methods like DEXA scans or hydrostatic weighing. The US Navy method, which this calculator uses, is a well-researched formula that correlates neck, waist, and hip measurements with body density. It provides a practical and affordable way to monitor body composition changes over time without expensive medical equipment or specialized facilities from healthcare providers.
Understanding your body fat percentage is important for assessing your overall health and fitness level. Unlike BMI, which only considers weight and height, body fat percentage distinguishes between fat mass and lean muscle mass. This gives a more accurate picture of your body composition and helps you set realistic fitness goals. Athletes typically have lower body fat percentages than the general population, reflecting their higher muscle-to-fat ratio and better physical condition overall.
This calculator uses the US Navy formula, which was developed by the U.S. Navy Physical Fitness and Health Promotion Program. The formula differs slightly for men and women due to natural differences in body fat distribution. For men, measurements include neck and waist; for women, the formula also includes hip measurement. While not as precise as clinical methods like DEXA scans, the Navy method is reliable for tracking progress when measurements are taken consistently using proper technique and equipment over time.
How to use this Body Fat Calculator
- Enter your sex (male or female) to select the appropriate calculation formula for your body type.
- Enter your height in centimeters while standing straight and barefoot with good posture.
- Enter your neck measurement in centimeters just below the larynx with tape held horizontal and snug but not tight.
- Enter your waist measurement in centimeters at the narrowest point for men or 2 centimeters above the navel for women.
- For women only: enter your hip measurement in centimeters at the widest point of the hips with feet together.
- View your estimated body fat percentage and health classification instantly based on your inputs.
FAQ
What is the US Navy body fat method?
The US Navy body fat method is a simple formula that estimates body fat percentage using circumference measurements of the neck, waist, and hips (for women). It's based on research correlating these measurements with body density and hydrostatic weighing results.
Does this body fat calculator send my data anywhere?
No. All calculations happen instantly in your browser using JavaScript. Your input data is never transmitted to any server.
Is the Body Fat Calculator free to use?
Yes, completely free with no limits or registration required.
How accurate is the Navy body fat estimation?
The US Navy method is generally accurate within 3-5% of more precise methods like hydrostatic weighing or DEXA scans when measurements are taken correctly. It's most useful for tracking changes over time in the same person.