Body Fat Calculator
Our Body Fat Calculator estimates your body fat percentage using basic body measurements. Unlike body weight alone, body fat percentage gives a clearer indication of how much of your total weight is made up of fat compared with other body tissues.
Enter your age, sex, height, weight, and the required body measurements to get an estimated body fat percentage. The result is intended as a practical reference for understanding body composition and tracking changes over time.
What Is Body Fat Percentage?
Body fat percentage is the estimated proportion of your total body weight that consists of fat. For example, if a person weighs 80 kg and has an estimated body fat percentage of 20%, approximately 16 kg of their body weight would be body fat, while the remaining weight would come from lean tissues such as muscle, bone, organs, and body water.
Body fat percentage and body weight are not the same measurement. Two people can have the same weight but different body fat percentages because their amounts of muscle and other lean tissue may differ.
How Does the Body Fat Calculator Work?
This calculator can estimate body fat using the U.S. Navy body fat method, which uses body measurements rather than relying on body weight alone. The measurements required depend on sex.
Measurements Commonly Used for Men
- Age
- Height
- Waist circumference
- Neck circumference
- Body weight
Measurements Commonly Used for Women
- Age
- Height
- Waist circumference
- Neck circumference
- Hip circumference
- Body weight
Measurements should be taken consistently because small differences in where or how a measurement is taken can affect the estimated result.
U.S. Navy Body Fat Formula
The U.S. Navy method estimates body fat from circumference measurements and height. The commonly used formulas are logarithmic rather than a simple weight-based percentage.
For men:
Body Fat % = 86.010 Γ log10(waist β neck) β 70.041 Γ log10(height) + 36.76
For women:
Body Fat % = 163.205 Γ log10(waist + hip β neck) β 97.684 Γ log10(height) β 78.387
These formulas use measurements in the units expected by the specific version of the equation. If your calculator accepts centimeters and kilograms, the measurements may need to be converted before applying a formula designed for inches.
Example of a Body Fat Calculation
Suppose a man has a height of 70 inches, a waist circumference of 34 inches, and a neck circumference of 15 inches. The U.S. Navy equation can use these measurements to produce an estimated body fat percentage.
The calculation is only an estimate. It should not be interpreted as an exact measurement of the amount of fat in the body.
Body Fat Percentage Ranges
Body fat percentages can vary according to sex, age, genetics, activity level, and other individual factors. General reference categories are sometimes used to provide context, but they should not be treated as strict health targets for every person.
| Category | Men | Women |
|---|---|---|
| Essential fat | Approximately 2β5% | Approximately 10β13% |
| Athletes | Approximately 6β13% | Approximately 14β20% |
| Fitness | Approximately 14β17% | Approximately 21β24% |
| Average range | Approximately 18β24% | Approximately 25β31% |
These ranges are general reference values and can vary between sources. A single percentage should not be used on its own to determine whether someone is healthy or unhealthy.
Body Fat Percentage vs. BMI
BMI is calculated from height and weight, whereas body fat percentage attempts to estimate the proportion of body weight that is fat. BMI does not directly measure body fat.
For this reason, body fat percentage can provide additional information about body composition. However, both measurements have limitations. A person with a high amount of muscle, for example, may have a relatively high BMI without having a high body fat percentage.
Why Use a Body Fat Calculator?
- Estimate your body fat percentage from basic measurements.
- Get additional context beyond body weight or BMI.
- Track changes in body composition over time.
- Use consistent measurements when monitoring fitness progress.
How to Measure Your Waist and Neck
For a more useful estimate, take your measurements carefully and use the same method each time. Keep the measuring tape level and avoid pulling it so tightly that it compresses the skin.
Taking measurements under similar conditions can also make comparisons over time more meaningful. If possible, record your measurements rather than relying on memory.
How Accurate Is a Body Fat Calculator?
A body fat calculator provides an estimate, not a direct measurement. The accuracy of the result can be affected by measurement technique, body shape, the formula being used, and individual differences.
More specialized methods, such as DEXA scanning or other professional body composition assessments, can provide different or potentially more detailed measurements. Results from different methods should not always be expected to match exactly.
Important Note
This calculator is provided for general informational and educational purposes. Body fat estimates are not a medical diagnosis and should not be used as the sole basis for making health or nutrition decisions. If you have concerns about your body composition, weight, or overall health, consider speaking with a qualified healthcare professional.