The main purpose of this study is to compare the test forms to the midi anchor test and the mini anchor test performance based on item response theory. The research was conducted with using simulated data which were generated based on Rasch model. In order to equate two test forms the anchor item nonequivalent groups (internal anchor test) was used in this research. The data were generated and analyzed using the R software. 100 replications were done for each different condition. The results obtained from this simulation study were evaluated according to the equating error (RMSE) and bias (BIAS) criterions. In the study, midi anchor generally produced better equating results than the mini anchor test with a few exceptions for most conditions.