A Simple Step-by-Step Guide on How to Measure for a New Front Door

Projections show that the global exterior door market will reach a value of $118.2 billion by 2025.

If you’re replacing your front door there are some things you need to do beforehand. Firstly, you need to know how to measure for a new front door. Doors come in all different sizes, and buying one that doesn’t fit would be a bit of a disaster.

For a guide on how to do this, keep reading.

How to Measure for a New Front Door

Installing a new front door is a relatively easy task, so you may well be able to do it yourself. All you need to do is make sure you know how it’s done.

You might just be replacing a door that’s past its prime, or you might want to upgrade to glass entry doors. Regardless of your reason, you need to measure for a new front door before you make your purchase.

1. Determine the Door Dimensions

Get the dimensions of the door you intend to replace. It might not measure exactly to the inch, so when you measure your front door round up each measurement to the nearest inch. This will give you the nominal door size.

If the door your replacing is a single door or one with a sidelight you just need to measure the door slab. If it’s a double door you need to measure the width of the two slabs combined.

2. Note the Jamb Width

This measurement should be taken between the backsides of the interior and exterior trims. This will ensure your door is the right thickness to fit flush with the wall. If the door is too thick you’ll need to add jamb extensions to make it look right. 

3. Take the Rough Exterior Opening

To get this measurement you’ll have to remove the interior trim. Measure from the top of the opening to the bottom of the sill between framing members. Your new door will have rough opening requirements, so make sure these match up.

4. Assess the Exterior Opening

Finally, you need to measure the outer exterior casing, again from the top of the trim to the bottom of the sill. You’ll also need to compare these with your new door to make sure it will fit.

If the door you intend to buy is too small there are a few things you can do:

• Find a different, wider door that will fit properly
• Order the door as standard and use strips of wood to fill the gap
• Order a door that has no exterior molding and make your own

Once you’ve got all your measurements and you’ve decided on your door you’ll be ready to order it and get to work.

What to Replace

Knowing how to measure for a new front door is just part of the process. When replacing an exterior door it’s best to also replace the frame, sill, and hinges at the same time. The old parts might not fit quite right which could be an issue down the line.

If you’re interested in more home improvement articles check out some of our other blog posts.