When a maintenance agreement has been made based on a contract printing rate and the contract number of printed sheets, an image forming apparatus can determine before an image is actually formed, whether or not terms and conditions will be exceeded. When a user instructs to copy, after all images of original documents are scanned, it can be determined whether or not the number of remaining printable sheets exceeds a certain number, e.g., 100. When the number of remaining printable sheets is not more than 100, after calculating an average per/page printing rate of the scanned image data, the converted number of sheets, which is converted using the contract printing rate, is calculated from the average printing rate, the contract printing rate, and the number of printed sheets for one copy job, and a screen used in inquiring whether or not to print is displayed.