How to measure a euro cylinder lock
To measure a euro cylinder lock properly, you need three measurements: (i) the overall length of the cylinder; (ii) the length from the internal end of the cylinder (i.e. the end on the inside of the door) to the fixing screw; and (iii) the length from the fixing screw to the external end of the cylinder (i.e. the end on the outside of the door). The two measurements to the fixing screw are together known as the ‘split size’.
If the overall length was 90mm and the split size was 55mm for the internal side and 35mm for the external side, the euro cylinder lock size would be written as “55/35 (90mm).
In order to measure your lock properly, we recommend removing it from the door first. Here’s our step-by-step guide:
1. Remove the cylinder lock before measuring
To ensure your measurements are accurate, we strongly recommend removing the lock from the door first. To remove a euro cylinder lock, simply insert the key into the lock, open the door and remove the fixing screw just underneath the lock. Then, simply push the lock from one side and remove it at the other. If the lock won’t come out, try adjusting the key slightly.
2. Measure the overall length
Measure the length of the cylinder chamber from one end to the other. Euro cylinder locks increase in length in 5mm increments. If the lock you’re replacing doesn’t sit flush with the door then bear that in mind when choosing a new lock and consider going for a lock that’s 5mm longer or shorter as required.
3. Take the internal measurement
Measure the length of the cylinder from the internal end of the chamber to the fixing screw which will be near the middle. The internal end will be the end on the inside of the door. It’s important not to mix up the internal and external ends as some cylinders are designed to be anti-snap (to stop an intruder gaining access by simply snapping the end of the cylinder) – to work as intended, the external side of the cylinder has to be on the outside of the door. Anti-snap euro cylinder locks will usually have the external side marked on the cylinder itself so you can double check before fitting them.
4. Take the external measurement
Measure the length of the cylinder from the fixing screw to the external end of the cylinder. Once you have this, you’ll then have all the measurements you need to order your new euro cylinder lock.
If you’re still not sure, check out this short video which shows each step: