Euro or Oval Cylinder

Cylinders come in two shapes: Euro or Oval. You can check which one you need
by having a quick look at your lock.

Euro cylinder shape

Euro profile cylinder

Most locks in the UK take the euro cylinder. This is the one we'd advise if you're choosing a new lock. It's narrower at the bottom with a larger rounded top, a bit like a lollipop.

Oval cylinder shape

Oval profile cylinder

An oval cylinder operates exactly like a euro cylinder. They're not as popular though which makes them slightly trickier to replace.

Euro cylinders come in more sizes than oval cylinders. There are far more brands to choose from,
and you get more features too, such as a thumbturn instead of a key, or symmetrical keys.

Thumbturn Cylinder

This type of cylinder works well on back doors or patio doors.
On the outside the cylinder is locked by a key while on the inside you just need to twist the thumbturn.

Thumbturn cylinder

A thumbturn cylinder is also useful in an emergency when a quick exit is required - simply twisting the thumbturn will unlock the door.

How to Measure a Cylinder Lock

Choosing the right cylinder lock is vital for ensuring your locks are reliable, and secure your home. It is important to make sure you choose the right type of cylinder, but it is equally important to get the right size cylinder.

Learn to measure your cylinder locks with our simple guide to make sure you find the perfect replacement cylinder. Protect your property against lock snapping and intruders with the perfect cylinder from

Measuring to replace a cylinder

How to Measure

Download Measuring Tool

When A and B are the same dimension, you need an Equal Cylinder. If they're different, you need an Off-Set Cylinder.

Measuring for a new cylinder

If you're measuring for a new door, you'll need to consider the door's width and any door furniture, such as handles or escutcheons.

Measure from the outside edge of the door (including furniture) to the centre of your door. This is dimension A and is called the External Size to Centre.

Next, measure from the inside edge of your door (including furniture) to the centre of your door to find dimension B, the Internal Size to Centre.

As a final check, measure from the outside edge to the inside edge (including all furniture) to find dimension C called the Overall Length.

If you've measured correctly the overall length, C, will be dimensions A and B combined.

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