The invention relates to a method for testing the real-time capacity of a system, especially a computer system, according to which a quantity of different tasks (τ) is to be executed, system costs being incurred by the execution of each task (τ). The aim of the invention is to provide an especially rapid and accurate method. To this end, in order to determine the total costs (Dbi(I)) for at least one time interval (I), the actual system costs (Dbi(I)) of the job of a first task are taken into account for said at least one first task, the actual system costs (Dbi(I)) of at least two jobs of the first task are taken into account for at least one first task, and other system costs are taken into account for at least one second task. The other system costs are determined by an approximation based on the actual system costs (Dbi(I)).