Body Fat Calculator Guide: Formula & Worked Example
Short answer
Body fat percentage using the U.S. Navy method. In the fixed example below, body fat is 16.4%. Your answer depends on the inputs and assumptions you choose.
Formula
Result = Body Fat Calculator calculation using gender, weight, height, neck, waist, hip (female only)
The inputs are gender, weight, height, neck, waist, hip (female only). Use the input scale shown beside each field and keep time periods and units consistent. Only round the final result for display.
Worked example
- Gender
- m
- Weight
- 70
- Height
- 178
- Neck
- 38
- Waist
- 85
- Hip (female only)
- 95
- Body fat: 16.4%
- Category: Fitness
- Fat mass: 11.5 kg
- Lean mass: 58.5 kg
Understanding the result
Body fat percentage using the U.S. Navy method. Start with the base example, then replace each value with the figure that matches your situation.
Gender
The example uses Male for gender. This is an illustration, not a recommended value. Keep the unit and time period shown by the field.
Weight
The example uses 70 kg for weight. This is an illustration, not a recommended value. Keep the unit and time period shown by the field.
Height
The example uses 178 cm for height. This is an illustration, not a recommended value. Keep the unit and time period shown by the field.
Neck
The example uses 38 cm for neck. This is an illustration, not a recommended value. Keep the unit and time period shown by the field.
Waist
The example uses 85 cm for waist. This is an illustration, not a recommended value. Keep the unit and time period shown by the field.
Hip (female only)
The example uses 95 cm for hip (female only). This is an illustration, not a recommended value. Keep the unit and time period shown by the field.
What the comparison means
The comparison changes only weight, keeping every other example input fixed. This isolates that input's effect on the primary result. It does not predict future outcomes.
This is a screening or planning estimate, not a diagnosis. Age, pregnancy, medication and individual medical history can change how the result should be interpreted.
Comparison
| Scenario | Input | Result |
|---|---|---|
| Lower input | Weight: 56 kg | Body fat: 16.4% |
| Base example | Weight: 70 kg | Body fat: 16.4% |
| Higher input | Weight: 84 kg | Body fat: 16.4% |
Common mistakes
- Using the wrong units for weight.
- Comparing results while changing more than one input at a time.
- This is a screening or planning estimate, not a diagnosis. Age, pregnancy, medication and individual medical history can change how the result should be interpreted.
Checklist
- Confirm gender.
- Confirm weight is expressed in kg.
- Confirm height is expressed in cm.
- Confirm neck is expressed in cm.
- Confirm waist is expressed in cm.
- Check the result against your source or provider.
Calculators Percentage Editorial Team
Calculator guides from the Calculators Percentage team. These introductory examples are educational, not professional advice.
Last reviewed:
This is a screening or planning estimate, not a diagnosis. Age, pregnancy, medication and individual medical history can change how the result should be interpreted.