When you’re ordering a replacement uPVC door, getting the measurements right is absolutely crucial. An incorrect size could lead to fitting problems, draughts, or even needing to reorder—costing you time and money. This guide will show you how to measure for a uPVC door properly, whether you’re replacing a front door, back door, or side door.
Why Measuring Accurately Matters
A perfectly measured door ensures:
-
Proper fit and insulation
-
Smooth and easy installation
-
Better security
-
Avoidance of costly returns or adjustments
Whether you’re installing it yourself or hiring someone, providing correct measurements will ensure everything goes to plan.
Tools You’ll Need
Before you begin, gather the following:
-
Tape measure (preferably a metal one for accuracy)
-
Notepad or phone to record measurements
-
Step ladder (if needed for taller frames)
-
Spirit level (optional but helpful)
How to Measure for a uPVC Door – Step-by-Step
📝 Tip: Take all measurements in millimetres (mm) and measure in at least three places—top, middle, and bottom. Always use the smallest measurement when ordering.
1. Measure the Width
Measure the width of the brick opening (not the old frame) at:
-
Top
-
Middle
-
Bottom
Write all three down, and use the smallest width for your order.
2. Measure the Height
Next, measure from the bottom of the lintel (or top brick edge) to the top of the threshold or floor. Again, take:
-
Left side
-
Centre
-
Right side
Use the smallest height measurement.
3. Deduct for Fitting Clearance
To ensure a snug but workable fit, deduct 10mm from both your final width and height measurements. This allows room for expansion foam, sealing, and adjustment during installation.
4. Check Door Swing & Threshold Type
Decide:
-
Opening direction – Inward or outward
-
Hinge side – Left or right (as viewed from outside)
-
Threshold type – Standard or low threshold (for easier access)
Extra Tips for Replacing an Existing Door
If you’re replacing an existing uPVC door:
-
Remove the old door (or carefully examine the frame) to measure the opening size accurately.
-
Don’t measure the door leaf—always measure the aperture.
-
If in doubt, take a photo and send it to your supplier for support.
Common Mistakes to Avoid
-
Measuring the old door instead of the opening
-
Not checking for out-of-square walls or frames
-
Forgetting to subtract 10mm for fitting clearance
-
Mixing up internal and external measurements
When to Call a Professional
If you’re unsure about any part of the measuring process, especially if your brick opening isn’t square or you’re dealing with a very old frame, it’s always a good idea to seek advice or hire a professional. Most suppliers will also offer support with measuring guides or even measuring services in some areas.
Need Help? We’ve Got You Covered
At Doorland, we make the ordering process as easy as possible. Just follow this guide on how to measure for a uPVC door, and you can confidently place your order online. Still unsure? Contact our friendly team—we’re happy to help.
Conclusion
Getting accurate measurements is the first and most important step to a successful door replacement. With this guide, you now know how to measure for a uPVC door confidently and correctly. Just remember: measure twice, order once!
