Never underestimate the transformative effect of a new front door. It can give your home’s exterior a new lease of life, add to your kerb appeal, make your home more secure, and even help you to stay warm in the winter months. But before you start shopping for any new door, it’s essential that you get the size right.

You could be forgiven for assuming that all external doors are the same size. But this is not necessarily the case. And if you buy the wrong size you could find yourself either wasting a lot of timber as you cut your door to size, or dealing with a lot of cold draughts coming into your home from outside.

Fortunately, you can count on Express Doors Direct to offer an outstanding range of external doors in a range of standard door sizes, styles and finishes. Whatever you’re looking for a new front or back door, our team can help you find the perfect fit.

Let us guide you through everything you need to know about sizing up your external doors. 

External door dimensions 

Your external doors are more than just a visual flourish for your home’s exterior. They also have serious implications for your home’s security and insulation. As such, it’s important to consider all the relevant dimensions when measuring door sizes. 

These include:

• Height
• Width
• Thickness 

Standard door sizes for external doors are different to internal ones. This is mainly down to door thickness. To provide adequate security and insulation, external door thickness needs to be at least 40mm, whereas interior door thicknesses can range between 35mm-40mm thick. They can also be even thicker if they are fire doors. You can find out more about internal door sizes using our guide.

Are front doors a standard size?

When replacing your exterior doors, you may wonder “what is the standard front door size?”.  While there are no specific building regulations stating that front doors have to be one specific size, there are door size parameters under which external doors must fall. As such, there is a fairly standard door size range for front doors. 

The most common exterior door height in the UK is 1981mm while the most common widths are 762mm and 838mm. The latter is found in buildings that were more recently constructed in order for them to meet accessibility requirements. External doors must be at least 40mm thick, but the most common thickness is 44mm.

Common external metric door sizes

 While 1981mm x 838 x 44mm is the most common external door size, and therefore largely considered standard, don’t worry if your front door does not conform to this size. There is a variety of common external door sizes readily available from retailers and manufacturers.

Some of the most popular dimensions include:

• 1981 x 762 x 44mm
• 1981 x 838 x 44mm
• 2032 x 813 x 44mm
• 2082 x 864 x 44mm
• 2134 x 915 x 44mm

Photo by Brett Jordan on Unsplash

What is the smallest external door size? 

If you have a small home with a narrow entryway, you may wonder if your smaller door deviates from the standard size. While it’s unlikely that your home’s door will deviate from the more common 1981mm in height, it may be smaller than 838mm in width. Especially if you live in an older property that was built before wheelchair accessibility was factored into the building regulations. It is rare for front doors to be shorter than 1981mm and less than 686mm in width.

Current UK building regulations place no restrictions on door height or door width, but your home’s main entranceway should have a clear single door width of at least 775 mm. This is the distance between your door jamb and the face of your door when opened. 

What are the largest standard door sizes?

Many people look to build a grand entrance for their home, installing external french doors or double doors.

Double doors will typically measure between 1981 x 1524 x 44mm and 1981 x 1676 x 44mm. Or between 1981 x 2438 x 44mm and 1981 x 2591 x 44mm with sidelights. Sidelights will typically add around 356mm to your doorway on either side. 

Door size conversion chart: Imperial & metric

Depending on when you were born and educated, you may have different preferences when it comes to using metric or imperial measurements. Some of us think in terms of millimetres, while others think in terms of inches.

For your convenience, we’ve created this conversion chart to help you make sense of the most common measurements and standard UK door sizes for your external doors.

External door sizes: building regulations

Both external and internal doors are subject to building regulations. 

Most of the building regulations that affect doors deal with:

• Protection and materials for glazed front doors (Part N)
• Ensuring fire safety (Part B)
• Creating sound insulation (Part E)
• Creating heat and energy insulation to conserve fuel (Part L)
• Providing disabled access (Part M)

This last entry is the only one that really impacts door sizes. In particular, it defines the requirements for door widths to allow for wheelchair access.

Building regulations state that all visitable dwellings must have a required door width of 775mm as a minimum for existing buildings and 1,000 mm for new buildings. A minimum standard width of 750mm is acceptable when the approach to the front door is straight-on. 

What size external door do I need?

While your external doors may fall under the common size range detailed above, it’s not a good idea to assume that it falls within this range. The best way to make sure is to check yourself using a tape measure. Keep in mind that your door may have been cut to size if the dimensions of your doorway are atypical.

It is also worth noting that while sidelights are fairly standard, not all conform to the typical width of 356mm, so it’s a good idea to measure doors separately from them.

Accuracy is essential when measuring your external doors, and you should avoid making estimations. We have a dedicated external door measuring guide to help you with this. However, if you are at all unsure, don’t hesitate to contact the expert team at Express Doors Direct. 

What if my external door frame and size isn’t standard?

If you live in an older property, a listed building, or a property that’s been custom-built, you may find that your door frames and door sizes are unconventional. If you’re having trouble finding front and back doors that meet your exact specification on our website, don’t worry.  

The majority of our wooden doors are available with a solid timber lipping. This means you can trim most external doors we stock to create a non-standard size door. This allows you a wider choice among our standard door sizes, perfect if your door frame and opening are only slightly taller or broader than the average width.

We also offer a bespoke exterior door service. We offer made to measure doors to meet your needs, ensuring a perfect fit even in doorways with unusual dimensions. 

Talk to a member of our team about this service using our contact form.Find your perfect fit with Express Doors Direct

Your choice of front door provides a perfect opportunity to boost your curb appeal and enhance your exterior aesthetic. So, why entrust it to anyone but the best? 

At Express Doors Direct, we can help you to find the perfect external door to fit your needs, with an incredible range of material, glazing, styles and finishes.