How to Measure Your Door
How to Measure for a
Composite Front Door
How to Measure
This guide is intended to assist experienced tradespeople or confident DIYers in measuring accurately.
Please note: we do not accept liability for incorrect measurements or surveys.
How to Measure for Your New Door
What You’re Measuring
You’ll need to measure the full width and height of the opening — that includes the frame and cill (not just the door slab).
Width
Measure across the top, middle, and bottom of the opening. Take the smallest of the three and subtract 10mm to allow for fitting clearance.
Height
Do the same vertically: measure on the left, centre, and right. Again, use the smallest measurement and deduct 10mm.
Check It’s Square
Measure the diagonals (corner to corner). If the two diagonal measurements differ by more than 5mm, the opening may not be square and could require adjustment.
Important
Measuring for a new front door must be done accurately. Incorrect measurements can result in delays, additional costs, or doors that do not fit correctly.
If you’re unsure at any stage, we strongly recommend choosing professional measurement and installation.
Measurements must be taken to the brickwork opening, not just the existing door slab.