Body Fat Calculator

Estimate Body Fat Percentage by U.S. Navy, ADA, and BMI Methods

About This Body Fat Calculator

This Body Fat Calculator estimates your body fat percentage using several commonly used methods, including the U.S. Navy Method, the American Diabetes Association equation, and the BMI-based body fat formula. It supports both metric units and US units.

In addition to body fat percentage, the calculator also estimates body fat category, body fat mass, lean body mass, ideal body fat for age, and the approximate amount of fat to lose to reach the selected ideal body fat level.

How to Use the Body Fat Calculator

1. Select Metric Units or US Units.
2. Enter your age, gender, height, and weight.
3. For the U.S. Navy Method, enter neck, waist, and hip measurements where required.
4. Check the American Diabetes Association option if you want to estimate body fat using age, gender, height, and weight only.
5. Click Calculate to view your estimated body fat percentage and related results.

What Is Body Fat Percentage?

Body fat percentage is the proportion of your total body weight that is made up of fat mass. Unlike body weight alone, body fat percentage can provide more insight into body composition because it separates fat mass from lean body mass, including muscle, bone, organs, and water.

Body Fat Percentage Formula

This calculator can use different formulas depending on the selected method.

U.S. Navy Body Fat Formula for Men

For US units, the male U.S. Navy body fat formula is:

Body Fat % = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76

For metric units, the male formula can be expressed as:

Body Fat % = 495 / [1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)] − 450

U.S. Navy Body Fat Formula for Women

For US units, the female U.S. Navy body fat formula is:

Body Fat % = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387

For metric units, the female formula can be expressed as:

Body Fat % = 495 / [1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)] − 450

BMI-Based Body Fat Formula

The BMI-based body fat estimate is calculated from body mass index, age, and gender.

For adults:

• Men: Body Fat % = 1.20 × BMI + 0.23 × Age − 16.2
• Women: Body Fat % = 1.20 × BMI + 0.23 × Age − 5.4

For children and teenagers:

• Boys: Body Fat % = 1.51 × BMI − 0.70 × Age − 2.2
• Girls: Body Fat % = 1.51 × BMI − 0.70 × Age + 1.4

American Diabetes Association Body Fat Equation

When the American Diabetes Association option is selected, this calculator uses age, gender, and BMI to estimate body fat percentage. This method does not require neck, waist, or hip measurements.

The equation used is:

Body Fat % = -44.988 + 0.503 × Age + 10.689 × Sex + 3.172 × BMI − 0.026 × BMI² + 0.181 × BMI × Sex − 0.02 × BMI × Age − 0.005 × BMI² × Sex + 0.00021 × BMI² × Age

In this equation, Sex = 0 for male and Sex = 1 for female.

BMI = weight / height² [kg/m²]

Body Fat Categories

Body fat categories vary by gender. This calculator uses common fitness-based body fat classification ranges.

Body Fat Categories for Men

Body Fat Categories for Women

Jackson & Pollock Ideal Body Fat Percentages

This calculator can also reference age- and sex-based ideal body fat percentages associated with the Jackson & Pollock body composition standards. These reference values provide a practical way to compare an estimated body fat result with a typical target level for a person's age and sex.

The reference points show that ideal body fat percentage generally rises with age. Women have higher reference values than men because of normal physiological differences and essential fat requirements. These numbers should be used as educational benchmarks rather than strict medical goals.

Jackson & Pollock Age-Based Reference Values

If a user's age falls between two listed ages, the calculator can estimate the ideal body fat percentage by interpolating between the nearest reference points. For example, an age between 30 and 35 would be evaluated between the corresponding 30-year and 35-year values.

These Jackson & Pollock reference values are intended to add context to the calculator result. Personal body composition goals may vary based on health status, athletic background, muscle mass, and professional guidance.

Example Calculation

Example input:

• Unit system: US Units
• Age: 28
• Gender: Female
• Height: 5 ft 8.5 in
• Weight: 150 lbs
• Neck: 1 ft 8.5 in
• Waist: 3 ft 2.5 in
• Hip: 3 ft 1.5 in

Using the U.S. Navy Method, the estimated body fat percentage is approximately:

Body Fat: 26.6%

Small differences may occur depending on whether the calculation uses the direct US-unit formula or converts measurements to metric before applying the metric Navy formula.

Body Fat Mass and Lean Body Mass

This calculator estimates body fat mass and lean body mass using the following formulas:

Body Fat Mass = Body Weight × Body Fat Percentage

Lean Body Mass = Body Weight − Body Fat Mass

References

The following government resources provide helpful information about body weight, BMI, physical activity, and healthy lifestyle habits:

• CDC: About Body Mass Index BMI
• NIDDK: Weight Management
• Move Your Way - U.S. Department of Health and Human Services
• CDC: Healthy Weight and Growth

Disclaimer

This Body Fat Calculator is for general informational and educational purposes only. It provides an estimate of body fat percentage and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Body fat formulas may not be accurate for everyone, including athletes, older adults, pregnant individuals, children, people with certain medical conditions, or people with unusual body composition.

Always consult a qualified healthcare professional before making decisions about weight loss, diet, exercise, medical treatment, or body composition goals.