How to measure a door latch

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Measuring a door latch can be done in just a few simple steps. Check out the guide below to find out more!

What is a latch?

A door latch is a mechanism that connects the door to the door frame.

What size are door latches in the UK

The most common UK internal door latches are typically tubular latches sized at 64mm and 76mm because they are the overall length of the latch or case. They can also be found in industry-standard sizes 102mm, 127mm and 152mm.

However, when it comes to the size of the latch, the size of your door and where the latch is to be installed will determine the final measurements.

There are also backset measurements; they are the distance from the faceplate of the latch to the centre of the follower. This will determine where the door handle or doorknob sits on the face of the door. Backset industry standard sizes are typically 45mm, 56 mm, 82mm, 107mm and 130mm.

How to measure a mortice latch

The latch size on a door handle is typically shown with the overall length of the case. However, if you need to confirm the door latch size alone, then follow these steps.

Step 1: Measure case size

The case size is, as seen below, the overall length of the latch case. Note down the measurement in millimetres.

Step 2: Measure backset size

The backset, as seen below, measures from where the spindle of the door handle is planned to sit. Measure to the central part of the backset and note the measurement once again in millimetres.