How to use this calculator
Enter the tape measurements requested for the selected formula and choose metric or imperial units. Review estimated body-fat percentage, fat mass and lean mass together.
How the estimate is calculated
The US Navy-style circumference equations use height, waist and neck for the male formula, with hip circumference additionally required for the female formula. This implementation converts dimensions to centimetres before applying its logarithmic density equation.
Fat mass is body weight multiplied by the estimated body-fat fraction. Lean mass is the remaining weight. The output depends on the measurement technique as well as the selected formula.
What the estimate cannot tell you
This is an indirect estimate, not a body-composition scan. Measurement placement and tape tension can affect the result. Inputs must keep the logarithmic terms valid, and an estimate outside 0–100% is rejected. Category labels are descriptive conventions and cannot diagnose health or establish a personalized goal.
Worked example
If an estimate is 20% at a weight of 70 kg, estimated fat mass is 14 kg and lean mass is 56 kg. This arithmetic example does not validate the underlying circumference estimate.