Door Size Guide

Development guide content — written for structure and internal-linking testing. Verify all sizing information against supplier data before launch.

How door sizes are described

Internal door sizes are usually quoted as width by height by thickness. Both metric and imperial size conventions are in common use in the UK, and the same door is often listed under both.

Measuring the leaf or the opening

If you are replacing a door into an existing frame, measure the existing door leaf. If you are fitting a new frame or lining, measure the structural opening. These are different measurements and using the wrong one is the most common ordering mistake.

Openings that are out of square

Measure the width at the top, middle and bottom, and the height at both sides and the centre. Work from the largest measurement, then plane down to fit. If the opening is significantly out of square, a made-to-measure door may be the better option.

Trimming allowance

Doors are supplied with a stated allowance for trimming. This varies by manufacturer and by door construction, and it is not safe to assume a standard figure. Always check the allowance for the specific door before ordering.

When a standard size will not work

We make doors to your exact sizes and alter existing doors in our own workshop. See Custom Doors or request a quote.

Related

Door Measuring Guide · How to Measure for an Internal Door · Shop internal doors