At DuPage Security Solutions, we believe that even the smallest measurements make a big difference in security. One of those critical dimensions is the backset—the distance from the edge of the door to the center of the lock bore. This measurement ensures that your lock aligns properly with the door’s edge, whether it’s beveled, radiused, or flat. A precise backset is essential for both function and aesthetics, especially in commercial and educational environments where durability and code compliance matter.
Common Backset Sizes
For standard door locks, two backset sizes dominate:
- 2-3/8″ – Typical for residential doors
- 2-3/4″ – Standard for commercial and institutional doors
You might also encounter:
- 5″ backsets – Less common, used in specialty applications
- 16″ backsets – Rare, mostly found in older or custom doors
Narrow Stile Aluminum Doors
When working with aluminum storefront doors, the backset options are different. These doors typically use:
- 31/32″
- 7/8″
- 1-1/8″
- 1-1/2″
Note: Exit trims for panic hardware generally don’t require a backset measurement.
Why Backset Matters
When replacing or upgrading a lock, matching the backset ensures a proper fit and smooth operation. At DuPage Security Solutions, we always verify this measurement before recommending hardware—because a misaligned lock can compromise both security and appearance. Some modern locks offer adjustable backsets, which can simplify installation. But when precision matters—like in school security retrofits or high-traffic commercial entries—we make sure every detail is dialed in.