Body Fat Percentage Calculator

Estimate your body fat percentage using the US Navy method with neck, waist, and hip circumference measurements.

Loading...
1. Select your sex (male or female) to use the correct formula. 2. Enter your height in the chosen unit system. 3. Measure and enter your neck circumference at the narrowest point. 4. Measure and enter your waist circumference at the navel. 5. For women, measure and enter your hip circumference at the widest point. 6. View your estimated body fat percentage, lean mass, and body fat category.

About This Tool

Body fat percentage is a far more useful measure of fitness than weight alone. Our Body Fat Percentage Calculator uses the US Navy circumference method, which has been validated against hydrostatic weighing and provides reasonably accurate estimates using simple tape measurements you can take at home.

For men, the formula uses neck and waist circumference along with height. For women, it adds hip circumference to account for differences in fat distribution. The calculator also estimates your lean body mass and displays which body fat category you fall into - from essential fat through to obese.

While the US Navy method is convenient and reliable for tracking trends over time, it is not as precise as methods like DEXA scans or hydrostatic weighing. For the most accurate results, measure at the same time of day, use a flexible tape measure, and take each measurement twice to ensure consistency.

Formula / How It Works

Men: %BF = 86.010 x log10(waist - neck) - 70.041 x log10(height) + 36.76. Women: %BF = 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387. All measurements in cm.

Frequently Asked Questions

The US Navy method estimates body fat using circumference measurements. For men, it uses waist and neck measurements along with height. For women, it adds a hip measurement. These values are plugged into a logarithmic formula that correlates well with more advanced methods.
For men, 10-20% is considered fitness to acceptable range, with athletes often at 6-13%. For women, 18-28% is fitness to acceptable range, with athletes at 14-20%. Essential fat (minimum for health) is about 2-5% for men and 10-13% for women.
Measure your waist at the narrowest point (typically at the navel for men). Measure your neck just below the larynx (Adam's apple), slanting slightly downward at the front. Women should measure hips at the widest point of the buttocks.
The US Navy method is accurate within about 3-4% for most people when measurements are taken correctly. It is most useful for tracking changes over time rather than determining an exact body fat number.
Measuring every 2-4 weeks is sufficient since body composition changes slowly. Always measure at the same time of day and under similar conditions for the most consistent results.

Related Tools

BMI Calculator

Calculate your Body Mass Index with a visual scale showing underweight, normal, overweight, and obese categories.

Health and Fitness

Calorie Calculator

Calculate your Total Daily Energy Expenditure (TDEE) and daily calorie needs using the Mifflin-St Jeor formula.

Health and Fitness

Ideal Weight Calculator

Find your ideal body weight range using multiple established formulas including Devine, Robinson, and Hamwi.

Health and Fitness

Macro Calculator

Calculate your daily protein, carbohydrate, and fat targets based on your calorie needs and fitness goals.

Health and Fitness

One Rep Max Calculator

Estimate your one-rep max for any lift using weight and reps performed. Includes percentage-based training loads.

Health and Fitness