backset

Backset is a term most commonly used in door hardware to describe the distance from the edge of a door to the center of the bore that accepts a lockset or knob. This spacing determines where the latch and lock components sit relative to the door edge and aligns with the strike plate on the door frame. The backset influences both the function and compatibility of a door hardware set.

In practice, backset is measured from the door edge to the center of the latch bore. In many regions, standard backsets are 2 3/8 inches (60 millimeters) and 2 3/4 inches (70 millimeters). Some locksets offer adjustable or multiple-backset options to fit different door designs, while others are fixed to a single backset. When selecting door hardware, it is essential to match the backset to the door preparation and strike plate to ensure smooth operation and proper alignment.

Practical considerations include the impact of backset on security and usability. A larger backset can place the latch farther from the edge, potentially affecting leverage and resistance to forced entry, while a smaller backset may be easier to operate for some users. Correct backset also ensures proper alignment with the strike plate and avoids interference with the door frame or hinges.

Beyond doors, the term backset can be used more generally to describe an offset or setback from an edge or reference line in other fields, though its most common usage remains in door hardware.