Determine Size & Swing
Once you’ve chosen your preferred style of door, you need to determine what size you need and how the swing of the door will open.
To determine the size, you need to measure the size of the rough opening - this is the width of your doorway. Our space is 32 inches wide, but we need to make sure there is enough room for the trim and the shims, so we sized down to a 30-inch prehung door.
To choose the swing direction, stand on the outside of the room and take a step in, looking left and right. Will the door back onto a piece of furniture or cover a light switch? There is no wrong way for it to swing, but it is important to take into consideration anything that might be blocked by the door. Ideally, when the door is open you want it tucked away in a space that makes sense in the room.