It takes about an hour to install a door. First, you have to remove the old door and all of its hardware. Then you have to measure the rough opening and cut the new door to size. Next, you have to attach the hinges and doorknob. Finally, you have to reattach the old hardware.

It depends on the type of door. A pre-hung exterior door can take as little as 30 minutes to install, while a custom-made interior door might take a few hours.