The invention relates to a system (1) for counting corrugations in a flexible material (100). The system is provided with a carrier (10) with a measuring area (12) and with aligning means (14) for aligning the flexible material in the measuring area, a light source for illuminating the measuring area, a camera for making one or more image recordings of the measuring area and a processor (23), which is arranged for counting the number of corrugations in one or more of the image recordings. The invention also relates to a method for counting a desired number of corrugations in a flexible material, for example pleats in fabric for a window covering, such as a pleated curtain. The invention furthermore relates to a computer program comprising instructions for carrying out the steps of the method.