Estimate body fat percentage using body measurements. Includes a simple category and educational guidance.
Use a tape measure on bare skin (not over thick clothing) for best accuracy.
Body fat percentage estimates how much of your body weight comes from fat mass versus lean mass (muscle, bone, organs, and water). Unlike BMI, which is a height-and-weight ratio, body fat percentage attempts to reflect composition. Many clinics and fitness programs use it to track trends over time.
This calculator uses a simple equation that estimates body fat percentage from BMI, age, and sex. BMI is derived from weight and height, and age and sex adjust the estimate. Waist and neck measurements are collected to encourage careful measurement habits, but this is still an approximation and not a substitute for professional body composition assessment.
Body fat categories are general guidelines. Athletic individuals may have different healthy ranges, and age, medical history, and pregnancy status can change what is appropriate. If you are using body composition for health decisions, consider professional assessment and discuss results with a clinician.
Is body fat percentage more useful than BMI? It can be, because it reflects composition, but it is still an estimate.
How should I measure waist and neck? Use a flexible tape and measure snugly without compressing skin.
Should I track a single number? Trends over time are usually more meaningful than a single reading.
This tool is for informational purposes only and should not be considered medical advice. Please consult a qualified healthcare professional for diagnosis or treatment.This tool is for informational purposes only and should not be considered medical advice. Please consult a qualified healthcare professional for diagnosis or treatment.