The POWERLIB SAS/IML software provides convenient power calculations for a widerange of multivariate linear models with Gaussian errors. The software includes the Box,Geisser-Greenhouse, Huynh-Feldt, and uncorrected tests in the univariate" approach torepeated measures (UNIREP), the Hotelling Lawley Trace, Pillai-Bartlett Trace, andWilks Lambda tests in multivariate" approach (MULTIREP), as well as a limited butuseful range of mixed models. The familiar univariate linear model with Gaussian errorsis an important special case. For estimated covariance, the software provides condencelimits for the resulting estimated power. All power and condence limits values canbe output to a SAS dataset, which can be used to easily produce plots and tables formanuscripts.