How to measure a mortice lock

A quick guide to assist in measuring and identifying the right replacement mortice lock

Selecting the right mortice lock can be difficult if you dont know what to measure and selecting the wrong one can mean that you will have to modify your door to suit it.  Please see the below which should assist you with measuring and identifying the right correct replacement mortice lock.


Deadlocks have a single deadbolt (usually operated by the key) and no latch.

A Case Depth
B Backset
C Case Height
D Forend Length
E Forend Width


Sashlocks have a deadbolt (usually operated by a key) and a latch (usually operated by door furniture)

A Case Depth
B Backset
C Case Height
D Centres
E Forend Length
F Forend Width
  Want to view the range of Mortice Locks available?

Now you know what measurements you need please browse our range of Mortice Locks and find the right one for your application.

  Can't find the answer you're looking for?

If you are still having trouble please take a look at our glossary or feel free to contact us for advice.

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