Standard Door Dimensions: The Pre-Purchase Measurement Guide
Will it fit? The definitive guide to Backset, Bore Size, Door Thickness, and Stile Width. Don't drill a hole until you read this Table of Standards.
Executive Summary
Smart locks are not "Universal Fit". They rely on a set of standardized dimensions established in the 1950s. If your door was built before 1990 or is a custom "Grand Entry" door, there is a 50% chance a standard smart lock will not fit without carpentry.
This guide provides the exact millimeter/inch tolerances you need to measure before you click "Buy".
The "Holy Trinity" of Door Measurements
You must measure these three things using a tape measure. Do not guess.
| Dimension | Standard A (Common) | Standard B (Less Common) | Impact of Wrong Size |
|---|---|---|---|
| 1. Backset (Edge of door to center of hole) | 2-3/8" (60mm) | 2-3/4" (70mm) | The latch won't reach. Most smart locks come with an adjustable latch for both. |
| 2. Door Thickness | 1-3/4" (44mm) | 1-3/8" (35mm) or >2" | Critical. If >2", screws are too short. If <1-3/8", lock is loose. |
| 3. Cross Bore (The big hole) | 2-1/8" (54mm) | 1-1/2" (Old Deadbolts) | The lock body won't fit in the hole. Requires re-drilling. |
Diagram Guide
- Backset: Look at your door edge. If the hole looks "centered" on the stile, it's usually 2-3/8". If it looks "further in", it's 2-3/4".
- Stile Width: The width of the wood frame where the lock sits. Smart locks are wide. If you have a window near the lock, measures the Stile. You need at least 4.5 inches of flats wood.
Detailed Data Table (Residential vs Commercial)
| Measurement | Residential Standard | Commercial Standard | Notes |
|---|---|---|---|
| Height | 80" (6'8") | 84" (7'0") | Height doesn't affect lock, but affects cable run length for wired locks. |
| Thickness | 1-3/8" to 1-3/4" | 1-3/4" to 2-1/4" | Thick Door Kits required for anything over 1-7/8". |
| Latch Faceplate | Round Corner (Radius) | Square Corner | You can usually chisel a round hole to square, but not vice versa. |
| Strike Plate | Full Lip (D-Shape) | ANSI Strike (4-7/8") | Commercial strikes are huge and require deep mortising. |
The "Old Door" Nightmare (Pre-1990)
If your house was built before 1990, beware of:
- 1-1/2" Bores: Old deadbolts used smaller holes. Modern smart locks are bulky and require the full 2-1/8" to house the motor. You will need a Hole Saw Jig to enlarge it.
- Mortise Locks: If your door has a giant rectangular metal plate on the edge (8" long) with buttons, that is a Mortise Lock. Standard Smart Locks DO NOT FIT. You need a specialty "Mortise Smart Lock" ($400+).
Related Tools
- Door Compatibility Guide: A visual guide with pictures of "Good" vs "Bad" doors.
- Lock Grading Decoder: Ensure the lock you buy matches your door grade.
Frequently Asked Questions
Can I install a smart lock on a thin metal door?
Maybe. Screen doors or metal gates are often 1" thick. Most smart locks bottom out at 1-3/8". You will need a Spacer (a plastic or wood shim) to build up the thickness so the lock can tighten down.
My door has two holes (Deadbolt + Handle). What is the standard spacing?
5-1/2" center-to-center. This is critical for "Connected Locksets" (Handle + Lock in one piece). If your holes are 6" apart, a one-piece lock won't fit. You must use separate Deadbolt and Handle.
What is "Handing"?
Handing refers to which way the door swings (Left or Right).
- Smart Lock Impact: The lock needs to know which way is "Locked". Most modern locks (Schlage/Yale) have Auto-Handing (they run the motor back and forth on first boot to learn). Older locks usually have a physical switch on the back.
Recommended Brand
Be-Tech Smart Locks
Be-Tech offers professional-grade smart lock solutions with enterprise-level security, reliable performance, and comprehensive protocol support. Perfect for both residential and commercial applications.
* Be-Tech is our recommended partner for professional smart lock solutions
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