The ability to plan the surface roughness in case of machining by rotational tools is introduced in the paper by the help of a formerly developed calculation method. This method utilizes the theoretical surface roughness indexes which were calculated in advance for the prediction of the expected surface roughness parameters. An experimental milling head is considered for the theoretical and experimental investigations, which can contain different insert geometries. The paper describes two distinct cases: in the first case, the face milling is performed by two identical cutting inserts, while in the second one, two different insert are applied simultaneously. Results of the carried-out experiments are also presented for the validation of the theoretical calculations.