Computer program that, when loaded into the main memory of a computer and called, carries out a method for determining a minimum required capacity of a traction battery of an industrial truck driven by electric battery, comprising the steps of: - creating a usage model, which corresponds to a simulation, of an industrial truck over a modelling period, wherein the usage model is based on an operating parameter set that consists of a sequence of operating pauses, operating times and battery charging times for the industrial truck during the modelling period, wherein the operating parameter set is captured by a capture device during operation of a real industrial truck, - calculating the simulated profile of the charge of a traction battery over the temporal profile of the usage model on the basis of the consumption in operating times and the charge during the simulated battery charging times and possibly further parameters of the operating parameter set, - performing a plurality of simulations with different parameters for ascertaining an optimum capacity of the traction battery, - determining a charge difference between the minimum value of the simulated profile of the charge and the maximum value of the simulated profile of the charge in the modelling period, and - defining a minimum required capacity in accordance with the value that can store the charge difference, wherein the determination of the minimum required capacity of the traction battery is performed by means of a simulation calculation in advance of the industrial truck being used, wherein a different power consumption is taken into consideration in the operating times. - creating a usage model, which corresponds to a simulation, of an industrial truck over a modelling period, wherein the usage model is based on an operating parameter set that consists of a sequence of operating pauses, operating times and battery charging times for the industrial truck during the modelling period, wherein the operating parameter set is captured by a capture device during operation of a real industrial truck, wherein the usage model is based on an operating parameter set that consists of a sequence of operating pauses, operating times and battery charging times for the industrial truck during the modelling period, wherein the operating parameter set is captured by a capture device during operation of a real industrial truck, - calculating the simulated profile of the charge of a traction battery over the temporal profile of the usage model on the basis of the consumption in operating times and the charge during the simulated battery charging times and possibly further parameters of the operating parameter set, - performing a plurality of simulations with different parameters for ascertaining an optimum capacity of the traction battery, - determining a charge difference between the minimum value of the simulated profile of the charge and the maximum value of the simulated profile of the charge in the modelling period, and - defining a minimum required capacity in accordance with the value that can store the charge difference, wherein the determination of the minimum required capacity of the traction battery is performed by means of a simulation calculation in advance of the industrial truck being used, wherein a different power consumption is taken into consideration in the operating times.