BAZI is a freely available Java-program implementing various apportionment methods for proportional representation systems. It offers divisor methods as well as quota methods. The extensive database permits to investigate the merits of the different apportionment methods on the basis of empirical data. A particular feature of BAZI is that it offers three options for multiple electoral districts. The user may choose between (1) separate evaluations for each district, (2) biproportional apportionments using divisor methods, and (3) a variant of the latter that is specifically tailored to the needs of the new Zurich electoral law of 2003. For these matrix apportionment methods thirteen algorithms and hybrid combinations of them are available. The BAZI program also offers to include minimum and maximum restrictions for vector and matrix apportionments. We present several empirical examples where these restrictions are essential.