The backset is the distance from the edge of the door to the spindle mechanism on the latch. Usually for a 63mm case measurement it will have a 44mm backset and for a 76mm case measurement will have a 65mm backset. The backset you choose is where your door knobs will sit on the door (where the spindle goes through).

How do you measure a door backset?

The backset is the measurement from the edge of the door to the center of the bore hole. Most door handle sets feature a 2-3/8" or 2-3/4" backset. To determine the backset on your door, measure the distance from the outer edge of the door, to the center, or highest point of the bore hole.

What backset should I use?

If you dont have any hardware on your door, just measure from the edge of the door to the center of the bore hole (the large hole where the door knob assembly is mounted). ... The most common backset is 2 3/8″ but 2 3/4" is also quite common - usually used on exterior doors.