The width, height, and jam depth of a door frame must be measured to get proper measurements for interior door replacement. The door itself should be removed to get the precise measurements needed to purchase an appropriate door replacement.
The width of a door frame is determined by measuring the width in three different locations and noting the smallest measurement taken. The height measurement is set by measuring from the top of the door frame to the floor on both the right side and the left side of the opening and writing down the smaller of the two measurements, and the jam depth is determined by the width of the wall the door frame is set in. Standard measurements for wall width are 4 9/16 inches or 6 9/16 inches.