What is the Body Fat Calculator?
The body fat calculator is a free online tool that helps you work out body fat quickly and accurately. It uses the standard formula US Navy method using log10 of body circumferences and height and shows the result instantly as you type, along with a full breakdown so you can see exactly how the answer was reached.
How to use this calculator
- Choose gender.
- Measure height, neck and waist (and hip for women).
- See your estimated body-fat percentage.
Formula used
US Navy method using log10 of body circumferences and heightExplanation of each input
- Gender โ the gender used in the calculation.
- Height (cm) โ the height used in the calculation.
- Neck (cm) โ the neck used in the calculation.
- Waist (cm) โ the waist used in the calculation.
- Hip (female) (cm) โ the hip (female) used in the calculation.
Understanding your result
- Body fat โ the calculated body fat in %.
Step-by-step calculation
For the example values Male, 170cm, neck 38, waist 85:
- Apply the formula:
US Navy method using log10 of body circumferences and height - Substitute the values: Navy formula
- Result: Body fat about 18%
Worked example
| Inputs | Male, 170cm, neck 38, waist 85 |
|---|---|
| Working | Navy formula |
| Result | Body fat about 18% |
Benefits and practical uses
This calculator saves you time and reduces errors when you need body fat. It is useful for students, professionals and anyone who wants a fast, reliable answer without manual calculation. Results update instantly, work in your browser and can be copied or shared in one click.
Assumptions and limitations
- US Navy circumference method.
- Accurate tape measurements required.
Frequently asked questions
How accurate is the Navy method?
It is a reasonable estimate (+/- 3-4%) but less precise than DEXA scans.
Disclaimer: This calculator provides general estimates for educational purposes only and is not medical advice. Consult a qualified healthcare professional for personal guidance.