There is no simple answer to how much the bottom line will be for your roofing project. A bid from your contractor should be based on square footage, the pitch of roof, accessibility, type of roofing material needed, 1- or 2-story home, removal of old roof (if necessary), roof permit and city license, and labor. The average cost to replace a roof runs from approximately $2,000.00 to $12,000.00 depending on the size of the roof and the quality of the workmanship and materials.