Work out relative fat mass instantly with clear inputs, formula shown and shareable results.
Relative fat mass needs only height and waist: RFM = 64 - 20 x (height/waist) for men, with 76 replacing 64 for women. A 175 cm man with an 88 cm waist gives 24.2%. Published against DEXA on NHANES data, it estimates body fat percentage more accurately than BMI, particularly for women.
Relative fat mass, men
RFM = 64 - 20 x (height / waist)
Relative fat mass, women
RFM = 76 - 20 x (height / waist)
These figures are population-average estimates, not a medical assessment or diagnosis. Body composition equations carry errors of several percentage points, and healthy ranges vary with age, ethnicity, muscularity and medical history. Discuss weight or body composition goals with a qualified clinician or dietitian.
Because it uses waist rather than weight, so it captures fat distribution and does not misclassify muscular people as over-fat.
Yes - the ratio must be dimensionless, so use centimetres for both or inches for both.