Backset Measurement Explained for Multipoint Door Locks

Backset is the distance from the edge of the door to the center of the handle spindle or cylinder hole.

It affects where the hardware sits on the door and is one of the first measurements we look at when helping someone replace multipoint lock parts.

The Simple Explanation

Backset does not change how the lock functions internally. It only controls positioning. If the backset is wrong, the handle and cylinder will not line up with the existing holes in the door. If you want to see how this connects with other door hardware measurements, our measurement terms glossary covers the most commonly confused dimensions.

 

How to Identify It on Your Door

• Measure straight from the door edge to the center of the handle hole.
• Keep the tape square to the edge and avoid measuring at an angle.
• 2-3/8 inches (60mm) is very common on residential doors.
• 2-3/4 inches (70mm) is common on commercial and some heavier entry doors.
• 3-1/2 inches (89mm) is used on certain commercial applications.

Why This Matters for Replacement

When replacing a gearbox or full lock strip, the backset must match the original or the hardware will sit too close to the edge or too far toward the center. We see this mistake lead to unnecessary returns more often than you would expect. If you are comparing options, you can browse parts that reference backset measurements and confirm what your door needs before ordering.

Key Notes

• Backset is a measurement, not a moving component.
• It controls where the handle and cylinder sit on the door.
• Measuring it correctly prevents ordering the wrong parts.