What is a door backset?

A door backset refers to the measurement from the edge of the door to the center of the doorknob or lockset borehole. It is a crucial dimension to consider when installing or replacing a door lock or latch.

The standard door backset size in most residential applications is 2-3/8 inches (60 mm) or 2-3/4 inches (70 mm), although some specialty doors may have different backset sizes. This measurement ensures that the door handle or lockset aligns properly with the strike plate on the door jamb, allowing the door to close and latch securely.

To determine the correct door backset, you can measure the distance from the edge of the door to the center of the existing doorknob or lockset borehole. Alternatively, you can measure from the edge of the door to the center of the hole in the door jamb where the latch engages when the door is closed.

When purchasing a new lockset or latch, it is essential to match the backset size to the existing measurement. Some door hardware manufacturers offer adjustable backsets, allowing for flexibility in installation.

Incorrectly sized backsets can result in improper alignment of the door lock, making it difficult to engage or disengage the latch. Therefore, it is crucial to ensure that the backset measurement is accurate when installing or replacing door hardware.