Body Fat Calculator: Estimating Body Composition From Measurements
Body fat percentage describes how much of your body weight is fat rather than muscle, bone and water. It is a far more useful health indicator than weight alone, and the US Navy tape method used here estimates it from height, neck, waist and (for women) hip circumference.
Typical ranges
- Men — essential 2-5%, athletic 6-13%, fitness 14-17%, average 18-24%, obese 25%+
- Women — essential 10-13%, athletic 14-20%, fitness 21-24%, average 25-31%, obese 32%+
- Women naturally carry more essential fat for hormonal and reproductive function.
Getting accurate measurements
Measure first thing in the morning before eating, with the tape snug but not compressing the skin. Take the waist at the narrowest point for women and at navel level for men, keep the tape horizontal, and repeat each measurement three times and average. Small tape errors move the result by whole percentage points, so consistency matters more than precision.
How the methods compare
DEXA scanning is the practical gold standard, hydrostatic weighing is close behind, and skinfold callipers are accurate in trained hands. Tape methods and bioelectrical impedance scales are less precise in absolute terms but track change well if you measure under identical conditions. For progress tracking, a consistent method beats an accurate one used inconsistently.
Key takeaways — Body Fat Calculator
- Body fat percentage explains composition that weight and BMI cannot.
- Measure at the same time of day, in the same way, every time.
- Track the trend over weeks rather than reacting to a single reading.