What Size is a Standard Door Frame?
The standard size for a door frame is 762mm in width. However, there technically isn’t a standard size - unlike the standard sizes for doors. Door frames are slightly different in that they’re customised from building to building.
Door frames often come 762mm in width, and this usually covers the gaps between the wall and the door on most standard doorways. The reason there isn’t technically a standard size for door frames is because the openings within a wall can vary quite often.
Measuring a Door Frame
If you already have a door that’s ready to install, you can figure out the door frame size that’s needed by measuring its width and height. To make sure you purchase the correct size door frame, take the width measurement of the door and add 2-inches. For the height, add 2.5-inches to the size of the door.