How to measure euro cylinders

How to mesure a euro cylinder

It’s quick and easy to measure your existing cylinder lock to replace it or to measure up for a new door.

Depending on your situation, follow the steps below, using the diagram as a reference. When A and B are the same dimension, you need a cylinder with 2 equal lengths. If they’re different, you’ll need an offset cylinder.

Measuring an existing cylinder lock 

You can measure up for a replacement euro cylinder without having to remove the existing lock from the door. To do this, start from step 3 of the instructions below. Alternatively, you can also remove the lock to measure it. To do this, start from step 1. You’ll also need the key, if your lock requires one to open.

  1. Release the cylinder

Once fitted, the cylinders are held in place with a central screw, located on the face edge of the door. Remove this screw to release the cylinder.

  1. Remove the cylinder

If your lock requires a key, you will need to insert and turn the key to ensure that it is in line with the cam and flush with the cylinder. To do this, insert the key to one end, turn the key to approximately 45 degrees left or right (depending on which side you insert the key) and pull the cylinder out. 

If your lock is a keyless thumb-turn euro cylinder, follow step 1 and simply turn the thumb-turn slightly whilst gently pulling out the cylinder.

  1. Measure the cylinder

To measure the cylinder lock, you will need to take two measurements. First, measure the external size to centre (A) by measuring from the end of the cylinder to the center of the screw hole. Repeat the process for the other side to get the internal size to center (B).

  1. Don’t forget to double check

To ensure accuracy, measure the overall length and ensure that it equates to the sum of A and B.

Measuring up for a new door

To measure up for a new door, you’ll need to measure the door’s width and any door furniture such as handles or escutcheons.

  1. Measure the external size to centre

Measure from the outside edge of the door, including the furniture, to the centre of the door. This is dimension A.

  1. Measure the internal size to centre

Then, measure from the inside edge of your door, including the furniture, to the centre of the door, to find dimension B.

  1. Measure the overall length to double check

To double check your measurements, measure from the outside edge to the inside edge of the door, including furniture. If you’ve done this correctly, the overall length should equal the sum of A and B.



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