Body Fat Calculator
Calculate your body fat percentage using the Navy Method formula. This calculator estimates body fat based on your waist, neck, and height measurements.
Calculate Your Body Fat Percentage
Enter your measurements to estimate your body fat percentage using the Navy Method.
Understanding Body Fat Percentage
Body fat percentage is a measurement of the amount of fat tissue in your body compared to your total body weight. It's a more accurate indicator of fitness and health than weight alone or BMI.
This calculator uses the U.S. Navy Method, which estimates body fat percentage based on circumference measurements at specific body sites. While not as accurate as methods like DEXA scans or hydrostatic weighing, it provides a reasonable estimate that's useful for tracking changes over time.
For the most accurate results, take measurements in the morning before eating or drinking, and be consistent with measurement locations. The waist should be measured at the narrowest point, the neck just below the larynx (Adam's apple), and the hips at the widest point around the buttocks.
Remember that healthy body fat percentages differ between men and women. Women naturally have more essential fat than men for reproductive health and hormonal functions.
Frequently Asked Questions
- What is body fat percentage?
Body fat percentage is the amount of fat mass in your body compared to your total body weight. It includes essential fat (needed for survival) and storage fat (accumulated fat). Unlike weight or BMI, body fat percentage directly measures the composition of your body, distinguishing between fat mass and lean mass (muscle, bone, organs, etc.).
- How is body fat percentage calculated?
This calculator uses the U.S. Navy Method, which estimates body fat percentage based on measurements of your neck, waist, and height (for men), plus hip measurements for women. The formula uses these measurements to estimate body fat percentage based on the relationship between circumference measurements and body density. For men: Body Fat % = 86.010 × log10(waist - neck) - 70.041 × log10(height) + 36.76. For women: Body Fat % = 163.205 × log10(waist + hip - neck) - 97.684 × log10(height) - 78.387.
- What is a healthy body fat percentage?
Healthy body fat percentages vary by gender and age. For men: Essential fat (2-5%), Athletes (6-13%), Fitness (14-17%), Average (18-24%), Above Average (25-30%), Obese (30%+). For women: Essential fat (10-13%), Athletes (14-20%), Fitness (21-24%), Average (25-31%), Above Average (32-38%), Obese (38%+). As we age, healthy ranges tend to increase slightly. Essential fat is necessary for basic physiological functions and going below these levels can cause health problems.
- How accurate is the Navy Method for calculating body fat?
The Navy Method provides a reasonable estimate with an error margin of about 3-4%. It's more accurate than BMI but less accurate than methods like DEXA scans (1-2% error), hydrostatic weighing (1-2% error), or air displacement plethysmography (2-3% error). The accuracy depends on proper measurement technique and can be affected by factors like water retention, recent exercise, and meal timing. For best results, take measurements in the morning before eating or drinking, and be consistent with measurement locations.
- How often should I measure my body fat percentage?
For tracking purposes, measuring once every 4-8 weeks is sufficient. Body fat percentage doesn't change dramatically in short periods (typically 0.5-1% per month with dedicated effort), and frequent measurements might lead to frustration due to normal fluctuations and measurement errors. Focus on trends over time rather than day-to-day changes. Take photos and track performance metrics alongside body fat measurements for a more complete picture of your progress.
- How do I take accurate measurements for the Navy Method?
For accurate measurements: 1) Use a flexible, non-stretching tape measure, 2) Measure first thing in the morning before eating/drinking, 3) Neck: Measure just below the larynx (Adam's apple), perpendicular to the neck axis, 4) Waist: Measure at the narrowest point (usually around the navel), at the end of a normal exhale, 5) Hips (women only): Measure at the widest point around the buttocks, 6) Keep the tape measure snug but not tight against the skin, 7) Take each measurement 2-3 times and use the average for best accuracy.
- Why is body fat percentage better than BMI?
Body fat percentage is superior to BMI because it directly measures body composition rather than just the relationship between height and weight. BMI can't distinguish between fat and muscle, so muscular individuals may be classified as "overweight" or "obese" despite having healthy body fat levels. Conversely, someone with normal BMI but high body fat (known as "skinny fat") may miss important health warnings. Body fat percentage provides more meaningful information about health risks and fitness status.
- How can I lower my body fat percentage?
To lower body fat percentage: 1) Create a moderate calorie deficit (250-500 calories below maintenance), 2) Consume adequate protein (1.6-2.2g per kg of bodyweight) to preserve muscle, 3) Perform resistance training 2-4 times weekly to maintain or build muscle, 4) Include cardiovascular exercise for additional calorie burning and heart health, 5) Prioritize whole, nutrient-dense foods, 6) Ensure adequate sleep (7-9 hours) and stress management, 7) Stay consistent - aim for 0.5-1% reduction in body fat per month for sustainable results.