2-3/8" or 2-3/4" — one wrong number and your new lever won't work. Here's everything you need to know about backsets before you order.
Before you order any door lever, knob, or deadbolt, you need to know one number: your backset. Get it wrong and the hardware physically will not work — the latch will not line up with the strike plate, or the bolt will not throw correctly. It is the most common pre-purchase mistake we see, and it is completely avoidable.
What "backset" actually means
The backset is the horizontal distance from the edge of the door (the side where the latch sits) to the centre of the bore hole — the large round hole that the lever or knob mechanism sits in. It is measured in a straight line, not along the door face.
In Canada and the United States, two backset sizes cover nearly every residential door:
- 2-3/8" (60 mm) — the standard for interior doors in most homes built after the 1980s. Also common on apartment and condo doors where the door stile is narrower.
- 2-3/4" (70 mm) — the standard for exterior doors and many higher-end interior doors with wider stiles. Also required by most deadbolts.
Some commercial or heritage installations use a 5" backset, but this is rare in residential work.
How to measure your backset
Open the door fully. Look at the existing latch or bolt. Measure from the flat edge of the door (the side the latch slides out of) to the centre of the round spindle hole. That is your backset. Do this before removing anything — measure the existing hardware in place.
If you are installing into a new door that has not been bored yet, most pre-bored doors come pre-drilled at 2-3/8". Custom doors can be bored at any dimension your millworker specifies.
Why interior and exterior doors differ
Exterior doors typically have wider stiles — the vertical frame members of the door panel — because they need to be stronger and better insulated. A wider stile means the bore hole is further from the edge, which means a larger backset. The 2-3/4" standard on exterior doors is almost universal across major hardware manufacturers including Emtek deadbolts and Taymor.
Interior doors with narrower stiles use 2-3/8" because there simply is not enough material to push the bore hole further in. Using a 2-3/4" backset hardware set on a 2-3/8" door would place the latch hole uncomfortably close to the edge and weaken the door.
What happens if you get it wrong
If the backset on the hardware does not match the door prep, the latch bolt will not align with the strike plate mortised into the door frame. The door either will not close properly, or will close but not latch. Neither is acceptable. Some hardware sets are adjustable — they ship with a latch that works at both 2-3/8" and 2-3/4" — but not all. Always confirm before ordering.
Adjustable vs. fixed backset latches
Most quality hardware manufacturers — including Emtek — include an adjustable latch with their lever and knob sets. This latch has a sliding faceplate that locks into position at either 2-3/8" or 2-3/4". You set it once during installation and it stays. If you are ever unsure of the backset ahead of time, choosing hardware with an adjustable latch gives you a margin of error.
Deadbolts are different. The backset on a deadbolt is almost always fixed, because the bolt mechanism itself determines the geometry. Always verify your door prep before ordering a deadbolt.
Quick reference
- Interior doors: 2-3/8" backset
- Exterior doors: 2-3/4" backset
- Deadbolts: almost always 2-3/4"
- When in doubt: measure the existing latch before removing it
If you are not sure of your backset and cannot measure it, call us before you order. It takes two minutes and saves a return shipment.
Have questions about your door prep? Contact our team or visit our Oakville showroom — we measure and specify hardware for projects across the GTA every week.
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