Measuring a cylinder lock: Get the right size in 3 steps
Easily measure the correct size – and if in doubt, we can adjust the size later.
Do you want to replace your cylinder locks? Then it is important to first cylinder lock to be measured and know the correct dimensions. A cylinder lock that protrudes too far is vulnerable to burglary, while a lock that is too short simply won't fit. In this guide, we'll explain exactly how to cylinder lock can be measured, with and without removing the lock.
Step 1: Remove the cylinder from the door
For the most accurate measurement, it is best to remove the cylinder from the door for a moment:
- Unscrew the locking screw (the bolt at the bottom of the cylinder) on the end side of the door [00:00:04].
- Insert the key into the lock and turn it a little bit (about 10 degrees) [00:00:14].
- Gently pull the key until the 'driver' is flush with the profile; the cylinder will now slide smoothly out of the door [00:00:21].
Step 2: Measuring the cylinder lock – determining the correct size
Place the cylinder on a flat surface. We always measure from the center of the screw hole to both ends.
Side A (Outside)
Measure from the center of the screw hole to the left side (to the end of the cylinder, excluding the key).
Side B (Inside)
Measure from the center of the screw hole to the right side.
Note: A standard cylinder is 30/30 (total 60mm). For example, if you measure 32mm, we will round this down to the standard size of 30mm. If you have a knob cylinder? The button itself never counts in the length measurement [00:01:19].
Measure a cylinder lock without disassembly?
Can't remove the lock? Use the book method:
- Hold a straight object (such as a book) against the door handle.
- Measure from the center of the locking screw in the door to the edge of the book.
- Do this for both the inside and outside.
Which cylinder suits your situation?
Now that you know the right size, it's important to choose the right type of cylinder lock. Read more about the difference between a standard cylinder lock, extra secured security locks or open multiple doors with identical cylinders.
Watch the video tutorial
In this video, Jordan shows exactly how to remove and measure the cylinder.
Done measuring?
Easily order the correct cylinder lock in your measured size. We supply SKG 3★ cylinders and can make them keyed alike free of charge if desired.