Determine the Backset of Your Door
The backset is the distance from the edge of the door to the center of the 2-1/8-inch bore hole. In the United States, there are two common backsets for residential door locks: 2 3/8 inches and 2 3/4 inches. Pack your locks with a 2-3/8-inch or 2-3/4-inch latch, depending on which backset you specify. Dummy sets have no latch and are surface-mounted so you can install a dummy set wherever you choose on the door.