An image forming apparatus includes an accommodation unit, feeding, conveying, and separating members, and detecting, control, image forming, and regulating units. The conveying member conveys a fed recording material. The separating member forms a nip and separates recording materials. The detecting unit detects that the recording material has been fed to the nip. The feeding member starts feeding an accommodated recording material and, where a recording material is fed to the nip, causes the feeding to be finished. An image is formed on a fed recording material. The regulating unit regulates an end on an upstream side. The control unit measures a period from a recording material feeding to detection that a recording material is fed to the nip. Based on the measured period, information is output indicating that a position of the regulating unit is deviated from a position according to a size of the accommodated recording materials.