Body Fat Calculator - Estimate Your Body Fat Percentage

What is Body Fat Percentage?

Body fat percentage is the total mass of fat divided by total body mass, multiplied by 100. It includes both essential fat (necessary for life and reproductive functions) and storage fat (accumulated in adipose tissue). Unlike BMI, body fat percentage directly measures fat mass and provides a more accurate picture of body composition.

Calculation Methods

US Navy Method

The US Navy method uses circumference measurements to estimate body fat. It is considered more accurate than BMI-based estimates because it accounts for body shape differences. The formula uses height, waist, neck (and hip for women) measurements.

Men: %BF = 495 / (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450
Women: %BF = 495 / (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450

BMI Method

The BMI-based method estimates body fat from your Body Mass Index. While less accurate, it only requires height and weight measurements. The formula adjusts for gender differences in fat distribution.

Body Fat Categories

Category	Men	Women
Essential Fat	2-5%	10-13%
Athletes	6-13%	14-20%
Fitness	14-17%	21-24%
Average	18-24%	25-31%
Obese	25%+	32%+

How to Take Measurements

Waist: Measure at the narrowest point, or at the navel for men
Neck: Measure just below the larynx (Adam's apple)
Hip (women): Measure at the widest point of the buttocks

Frequently Asked Questions

What is a healthy body fat percentage?

Healthy body fat ranges vary by gender and activity level. For men, 10–20% is generally healthy (athletes 6–13%, fitness 14–17%, average 18–24%). For women, 18–28% is generally healthy (athletes 14–20%, fitness 21–24%, average 25–31%). Essential fat is higher in women (10–13%) than men (2–5%) due to reproductive functions. These ranges are guidelines; individual health depends on many factors beyond body fat percentage.

How accurate is the US Navy body fat method?

The US Navy circumference method is considered one of the most accurate non-clinical methods, with an accuracy of ±2-3% compared to hydrostatic weighing or DEXA scans. It works best when measurements are taken carefully at the correct anatomical landmarks. For best results: measure at the narrowest waist point, just below the Adam's apple for neck, and at the widest hip point for women. Consistency in measurement technique matters more than absolute precision.

What is the difference between the Navy method and BMI method?

The Navy method uses actual circumference measurements (waist, neck, hip) and height, making it more personalized and accurate than the BMI-based method, which only uses height and weight. The Navy method accounts for where fat is distributed in the body, which BMI cannot do. Always prefer the Navy method when you have the required measurements.

How do I take accurate body measurements?

For the most accurate results: (1) Measure waist at the narrowest point (usually at navel level for men), (2) Measure neck just below the larynx with tape sloping slightly downward, (3) For women, measure hips at the widest point of the buttocks. Use a flexible, non-stretchable tape measure. Take measurements in the morning before eating or drinking. Keep the tape snug but not compressing the skin. Repeat 2-3 times and use the average.

Can body fat percentage change without weight change?

Yes, absolutely. This is called body recomposition. When you gain muscle and lose fat simultaneously, your weight may stay the same while your body fat percentage decreases. This is why tracking body fat percentage is often more useful than tracking weight alone, especially for people who are strength training or starting a new exercise program.