Measure Up for Perfect Fit: How to Measure Up for Internal Doors

When it’s time to replace your internal doors, it’s easy to get swept away browsing beautiful new door styles, or considering all the accessories, handles and hinges that could complement your decor. But the job itself requires a few simple steps to get right, whether you’re undertaking the whole project yourself, or looking for a professional door installer to help.

So before you log on to purchase the perfect new door, or perhaps even talk to an installer to source a quote, it always pays to take accurate measurements. That way, you know the size of door you need, and there’s no risk of taking delivery of a wrongly sized door that needs replacing or returning.

Grab a tape measure, a paper and pencil and follow this guide on how to measure for an interior door replacement.

Measuring the door frame

1. First, start with the width.

Measure the door frame from left to right, across the top, middle and bottom. The largest measurement is your door width, so note it down.

2. Second, measure the height.

Take one measurement from the left hand side, one in the centre and one on the right. Once again, the largest measurement is your door height.

3. Third, measure the depth of the door frame.

This is the part of the frame where the door will fit when it’s closed. Most internal doors will come in one of three standard thicknesses: 35mm, 40mm or 44mm, the latter normally being fire doors. So your depth should be close to one of these measurements.

Choosing the right door

Now you have all your measurements – the width, height and depth – you’re ready to source your replacement door.

Our catalogue offers all sorts of designs and styles, with finishes to suit your decor. So find one that works for you, then select the appropriate sizing based on the measurements you’ve recorded. Remember, if you’re looking for a 44mm depth internal door it’s likely you’ll need to purchase a fire door.

Things to consider

Though measuring up for internal doors is something anybody can undertake, there are definitely a few extra things to be considered.

Always think about your flooring. If you’re in the middle of a renovation and you intend to change your flooring, then you’ll need to take the depth of this into account.

You may also be faced with a non-standard frame, especially in a period property, or even no frame at all. In this case, it’s always worth considering choosing a standard size – especially if you’re installing a new frame too. Remember, most of our internal doors can be trimmed down by between 4mm and 30mm dependent on design- you can check lipping and trimming allowances on our product pages, and find out more in our guide to fitting a new internal door.

If you do still need a door to fit an unusual frame size, it might even be worth commissioning a fully bespoke door. That’s something our expert team can help with, and we offer a range of styles and solutions in bespoke sizes. Get in touch to find out more, or read our guide to bespoke doors.