What is backset on a door?

Backset is the distance between the edge of a door and the center of the hole for the door handle or lock. It is an important measurement to consider when installing or replacing door hardware. The standard backset in the United States is 2-3/8 inches or 2-3/4 inches, but other sizes are available, and it is essential to match the backset of the door with the backset of the hardware to ensure proper installation and function. Some modern locks may have adjustable backsets, which can be useful in situations where the door has an unusual thickness or location.