Door Lock Backset Measurement

Two standard backsets are 2 3 8 and 2 3 4.

Door lock backset measurement.

2 3 8 inches and 2 3 4 inches. The backset measurement is the distance from the centre of the keyhole to the leading edge of the lock. Most commercial doors have a backset of 2 3 4 inches 69 8 mm while residential doors measure 2 3 8 inches 60 3 mm. These equate to case sizes of 2 1 2 or 3 in imperial measurements.

In the uk and much of europe these dimensions can vary from 25 to 60 mm and many medallion knobs are placed in the center of the door creating a very large backset. C the case height. Backsetthe distance from the edge of the door to the center of the lock bore. Dead bolt latches top 2 3 4 bottom 2 3 8 note.

In the united states there are two common backsets for residential door locks. The backset is the distance from the edge of the door to the center of the 2 1 8 inch bore hole. 5 backsets are only available for some schlage locks and some kwikset locks. The backset is measured by placing a tape measure or ruler from the center of the keyhole to the forend of the mortice lock.

Other backsets include 2 used by national and lori lock and 5 used by weiser weslock kwikset and others. The most common sizes here are 44mm on a 64mm 2 5 lock case and 56mm on a 76mm 3 lock case. Sometimes it s easier to measure from the edge of the door to the highest point on the bore hole. Mortised latches come in a radius corner rounded on the edges or a squared corner configuration.

Check the other dimensions too most of our pages show plate and lock case dimensions. The most common backset is 2 3 8 but 2 3 4 is also quite common usually used on exterior doors. There is a range of backset long body locks at 20mm 25mm 30mm 35mm 40mm 50mm and 70mm. To do this measure the backset distance of your old lock.

These smaller backset sizes are generally european and some are still in use today. 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. Pack your locks with a 2 3 8 inch or 2 3 4 inch latch depending on which backset you specify. Standard backsets are either a 2 3 8 backset or 2 3 4 backset.

Falcon used to make a 5 backset that would work with emtek hardware but i believe it is no longer available. This is very important when replacing locks because you don t want to have to drill new holes if you can help it.