Body Fat Percentage Calculator

Most validation studies show the Navy method agrees with DEXA within ±3-4 percentage points on average for the general population. It tends to be less accurate at very low body fat (under 8% for men) and very high body fat (over 40%). For population-level or progress-tracking purposes, it is one of the best no-equipment methods available.

Food and liquid temporarily expand your waist circumference, which inflates the Navy estimate. Always measure in the morning before eating or drinking for a consistent baseline. Measure at the same phase of the menstrual cycle for women, as hormonal fluctuations cause water retention that affects waist and hip measurements.

In decreasing order of cost and accuracy: DEXA (±1-2%), hydrostatic (underwater) weighing (±1-3%), BodPod (±2-3%), multi-site skinfold calipers by a trained technician (±3-4%), single-site or home bioelectrical impedance (±5-8%). Tape methods sit in the middle range.

Both can be simultaneously correct. BMI measures mass-to-height, while the Navy method estimates fat fraction. A person with low muscle mass can have a normal BMI but carry excess fat (a condition called 'normal-weight obesity'). Body fat percentage is a more direct indicator of metabolic health risk. Discuss unusual discrepancies with your healthcare provider. This calculator is for informational purposes only and does not constitute medical advice.