An image forming apparatus including: an image formation unit including an accumulation unit accumulating toner, and forms an image based on image data using the accumulated toner; a measurement unit measures toner density of an developer in the accumulation unit; a replenishment unit replenishes toner to the accumulation unit from an attached container; a first determination unit determines a first value based on the image data; a second determination unit determines a second value based on the measurement result of the measurement result; a third determination unit determines a third value by accumulating the second value; and a controller controls the replenishment unit based on the first value, the second value, and the third value, wherein in a case where the container has been replaced, the third determination unit changes the third value into a predetermined value before the difference is determined by the second determination unit.