Image forming apparatus

An image forming apparatus comprising:

• a photosensitive member;
• a toner storage portion configured to store toner;
• a developing member configured to bear the toner stored in the toner storage portion, supply the toner to the photosensitive member, and develop a latent image on the photosensitive member into a toner image;
• an attachment portion to which a replenishing container containing toner is attached, the attachment portion being configured to allow toner replenishment from the replenishing container into the toner storage portion in a state where at least a part of the replenishing container is outside the image forming apparatus;
• and
• a control unit configured to calculate a toner consumption amount by multiplying a count value correlated with the number of pixels constituting the toner image by a coefficient, the control unit being configured to change a value of the coefficient in a case where the toner replenishment is performed.