Precision is key when it comes to measuring a door. A few millimetres out can lead to draughts, awkward fitting, or a door that won’t close properly.
This short guide explains how to measure in millimetres, whether you’re fitting into an existing frame or starting from scratch, plus how to account for gaps, trimming, and bespoke sizes.
Measuring the Frame or Opening
If you’re replacing a front door, take your measurements from the frame (not the old door) as it may have changed shape over time.
For openings without a frame, measure brick-to-brick across the top, middle, and bottom, noting the smallest width. Then do the same vertically on the left, centre, and right sides, again recording the smallest measurement.
This ensures the best possible fit and avoids costly mistakes later on.
Allowances, Gaps and Trimming
Leave clearance gaps of about 3mm at the top and sides and roughly 9mm along the bottom so the door can open freely.
Most modern doors feature a lipping – solid timber edging that allows for a little trimming to fine-tune the fit.
Always follow the manufacturer’s guidance on trimming limits to prevent damaging the structure or voiding any warranties.
Standard UK Door Sizes and Bespoke Options
The most common UK internal door size is 1981 × 762 × 35 mm (around 6’6” × 2’6”), though other standard options include:
- 1981 × 686 × 35 mm (6’6” × 2’3”)
- 1981 × 838 × 35 mm (6’6” × 2’9”)
Fire doors (FD30) are slightly thicker at 44 mm. If your doorway doesn’t fit one of these standard sizes, or if the frame is uneven, a bespoke door can be made to your exact dimensions.
Grab a sturdy metal tape measure, pencil, and notepad. Make sure trims and obstructions are removed before starting.
Always measure in millimetres for accuracy, and record the smallest figures for width, height, and depth.
Finally, measure the frame depth and the rebate (where the door rests in the frame) to ensure perfect alignment and a professional finish.
If measuring up feels like a bit too much, don’t worry, the experts at James Oliver will take care of it for you. It’s all part of the service when you choose one of our doors.
LOOKING FOR A NEW REPLACE DOOR?
From French and patio to bi-folding, we offer an incredible variety of doors inlcuding the latest front and back door designs, all of which are made to measure for the perfect fit to your home.
LOOKING FOR A NEW REPLACE DOOR?
From French and patio to bi-folding, we offer an incredible variety of doors inlcuding the latest front and back door designs, all of which are made to measure for the perfect fit to your home.
REQUEST YOUR FREE QUOTE
Simply fill in your details for your free, no obligation quotation, and click "Get Quote"
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Nibh sit amet commodo nulla facilisi. Ut faucibus pulvinar elementum integer. Egestas pretium aenean pharetra magna. Arcu risus quis varius quam quisque id diam vel quam.
Lorem ipsum dolor sit met, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna Alice. Dui id ornare arcu odio ut sem nulla pharetra. Viverra nam libero justo laoreet sit amet cursus. Aliquam vestibulum morbi blandit cursus. Facilisi nullam vehicula ipsum a arcu cursus vitae congue. Gravida cum sociis natoque penatibus et magnis dis parturient. Nibh sit amet commodo nulla facilisi. Ut faucibus pulvinar elementum integer. Egestas pretium aenean pharetra magna. Arcu risus quis varius quam quisque id diam vel quam.
LOOKING FOR A NEW REPLACE DOOR?
From French and patio to bi-folding, we offer an incredible variety of doors inlcuding the latest front and back door designs, all of which are made to measure for the perfect fit to your home.
LOOKING FOR A NEW REPLACE DOOR?
From French and patio to bi-folding, we offer an incredible variety of doors inlcuding the latest front and back door designs, all of which are made to measure for the perfect fit to your home.
REQUEST YOUR FREE QUOTE
Simply fill in your details for your free, no obligation quotation, and click "Get Quote"