An image forming apparatus includes: a holding unit configured to hold image processing coefficients, each of which representing a relationship between an input density and an output density of an image signal output to an image forming unit; and an updating unit configured to update an image processing coefficient based on the relationship between densities of measurement images and densities of image signals for forming the measurement images. The updating unit is further configured to, when a maximum value of an output density of the image processing coefficients is smaller than a maximum value of the density of the image signal, form at least one first measurement image in accordance with an image signal indicating a density higher than the maximum value of the output density of the image processing coefficients.