An image forming apparatus includes a controller configured to control a first and a second voltage applied to a transfer device when transferring an image to a first and a second side of a recording material, respectively. The controller controls a mode that outputs a test chart on which at least one of a plurality of first test images for adjusting the first voltage and a plurality of second test images for adjusting the second voltage is formed. In a case of forming the second test images on a second side of the test chart, and before forming the second test images, the controller forms a plurality of predetermined toner images under a same image forming condition on a first side of the test chart so that the predetermined toner images are formed on a plurality of predetermined areas overlapping each area where the second test images are to be formed.