A determination device includes an acquisition unit that acquires an output characteristic representing a relationship between a gradation value corrected by a correction unit in accordance with a predetermined correction characteristic and a measured value of a density of a toner image output by an output device for the gradation value; an estimation unit that estimates a density of a toner image output by the output device for a predetermined reference gradation value when the reference gradation value is not within a range of the corrected gradation value, the estimation being performed based on the output characteristic acquired by the acquisition unit; and a determination unit that determines whether or not the correction characteristic needs to be changed by comparing the density estimated by the estimation unit with a predetermined threshold.