Body fat calculator
HealthEstimate body fat percentage using circumference-based formulas and track body composition trends.
Your results
Estimate your body fat percentage using anthropometric measurements.
How body fat is estimated
For men, the estimate uses the U.S. Navy method. For women, this starter uses a simplified circumference estimate when hip data is not available, so treat the result as directional.
Best use for this estimate
Body fat tools work best for watching trends over time with consistent measurements. Absolute accuracy can vary based on tape placement and body shape.
Frequently asked questions
Answers to the most common questions about this tool.
How is this result calculated?
It uses the method and inputs described on this page to provide an informational estimate.
How accurate is the result?
It is an estimate and should be interpreted as a guide, not an exact measurement.
When should I seek professional advice?
Seek qualified advice for symptoms, pregnancy, illness, medication use, or clinical decisions.
What information do I need to enter?
Enter current, accurate details and select the correct units before calculating.
What can affect this estimate?
Individual factors such as health, activity, body composition, and measurement technique can affect it.
Sources and methodology
Methodology: Circumference body-fat estimate
For men it applies a US Navy-style circumference equation. For women it uses a ToolsRL approximation based on height, waist, and neck.
No external source is attributed to the female approximation. Future improvement: include hip circumference and a published equation.
References
No external reference is required: the mathematical calculation is described above.
Last reviewed
July 15, 2026