The aim of this study was to estimate body fat percentage through circumference of different parts of body by hydrodensitometry (hydrostatic underwater weighing) as the criterion method and to develop related equations. 158 male students of Isfahan University (mean age: 21.6 yrs, height: 174 cm, weight: 69.04 kg, body fat percentage: 15.61 kg, BMI: 22.59) were randomly selected. These subjects filled in the consent form and medical record questionnaire. Body density was estimated through underwater weighting. The RV was estimated through equation. Height, weight, and circumference of upper and lower body and trunk were measured at eight parts of the body. Using linear regression equations, Pearson correlation coefficient and stepwise method, 5 equations were developed. Correlation coefficients between weight and circumference of different parts of the body with criterion test were acceptable. Two equations with higher coefficient of determinant were as follows:

TBF (kg) = 5.924 + (0.655 *w) – (0.490*LA) + (0.303 *CC) + (0.197 * HC)
R= 0.901 R2 = 2.60438 SEE = 0.812
TBF (kg) = 2.413 + (0.358 * W) –0.003 * (LA2) + (0.098 * SCCAUA) + 0.001 * (CC2) R= 0.905 R2 = 0.82 SEE = 2.51344

W= weight, LA= abdominal lower circumference, CC= chest circumference, HC= Hip circumference, SCCAUA= Sum of chest and abdominal upper circumference