Free Body Fat Calculator
Use this free Body Fat Calculator to estimate your body fat percentage and better understand body composition using a practical measurement-based formula.
Enter your details below to calculate your estimated body fat percentage based on gender and body measurements.
How to Use This Body Fat Calculator
Follow these steps to estimate your body fat percentage using body measurements.
- Select your gender.
- Enter your height in centimeters.
- Enter your neck and waist measurements.
- If you select female, also enter your hip measurement.
- Click the calculate button to see your estimated body fat percentage.
This tool is useful for body composition tracking, fitness planning, and measuring progress more clearly than body weight alone.
What Is Body Fat Percentage?
Body fat percentage is the proportion of your total body weight that comes from fat mass. It gives a better picture of body composition than body weight alone because it separates fat mass from lean mass.
Two people can weigh the same but have very different body fat percentages depending on muscle mass, fat distribution, and body composition.
Why Use Our Body Fat Calculator?
- Estimate body fat percentage quickly
- Track body composition progress over time
- Use a more useful metric than body weight alone
- Support fitness, fat loss, and health goals
- Get a simple tool that works on mobile and desktop
How This Body Fat Calculator Works
This tool uses the U.S. Navy body fat formula, which estimates body fat percentage from body measurements. It uses different equations for men and women because fat distribution patterns are different.
For men, the formula uses height, neck, and waist measurements. For women, it uses height, neck, waist, and hip measurements.
Body Fat Formula Used
The calculator uses the U.S. Navy method and converts centimeters to inches internally before calculation.
Men: Body Fat % = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
Women: Body Fat % = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
These equations estimate body fat percentage based on circumferences rather than body weight alone.
Body Fat Categories
Body fat percentage can be interpreted differently for men and women. General categories are useful for understanding whether body fat levels are low, healthy, or high.
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Higher Body Fat | 25%+ | 32%+ |
Body Fat Calculation Example
Example for a man: height 175 cm, neck 40 cm, waist 85 cm.
The calculator converts these measurements and applies the U.S. Navy formula to estimate body fat percentage. The result may fall somewhere in the fitness or average range depending on the final number.
Example for a woman: height 165 cm, neck 34 cm, waist 75 cm, hip 95 cm. The calculator uses the women’s equation and estimates the body fat percentage based on those measurements.
Why Body Fat Percentage Matters
Body fat percentage helps you understand body composition more clearly than body weight or BMI alone. It is useful for tracking fat loss, muscle-building progress, fitness goals, and long-term body composition changes.
People often use body fat percentage along with BMI, weight, and measurements to get a broader picture of health and physique changes.