The aim of this study was to compare and validate the selected methods for estimating fat percentage. For this purpose, 30 inactive female students of Shahid Rajaei University (Age=20.93±1.91; Height=164.73±4.57cm; Weight=56.65±8.02 Kg) were selected voluntarily. They were randomly placed in one of the four different conditions (Digital, Harpenden, Plastic Calipers and Electrical Bioimpedance) on 4 separate days, in a crossover design for estimating fat percentage. Measurements were performed from 3 points (the triceps, iliac and femoral). The Results of repeated-measures ANOVA and Bonferroni post hoc test indicated that there were significant difference between harpenden and plastic calipers (P=0.045) and between digital and plastic calipers (P=0.003). The results of Pearson correlation coefficient indicated that There was a high correlation between digital and harpenden calipers as well (R=0.898, P= 0.000). Also the most Regression coefficient was allocated to digital caliper (β=0.817) and electrical bioimpedance (β=0.244) respectively and plastic caliper had the lowest place (β=0.14). It is worth noting that the overlap of predictive variable of harpenden caliper was R2 = 0.839 According to these results, it is recommended to use harpenden caliper for estimating fat percentage first. If there is no access to this caliper, you can use digital caliper and electrical bioimpedance respectively. Moreover, plastic caliper must be used with caution.