New Website New Products Same Low Prices
01530 273365 | 0844 692 3828
Mon-Fri: 9 AM - 5.30 PM
sales@justdoorsuk.com
Nationwide Delivery* In 5-15 Working Days
Price Promise Guarantee We'll beat any online price
No.1 Rated UK's top rated double glazing supplier

How to measure a double glazed upvc window and external door

These guidelines are to help you measure for a new double glazed door and/or window and make an accurate measurement.

Measure the opening outside on both the height and width. Always measure the exact brickwork opening and not the old frame or door.

Measure brick to brick in at least three different places and deduct 10mm from both the final height and width measurements to allow for 5mm fitting allowance around the new frame. This will enable you to ensure the new frame sits plumb and square once in the aperture. Spacers and filler will then be required to secure the frame into place and fill any gaps.

Please note: We are unable to accept responsibility for incorrect measurements. If you are unsure we recommend that you consult a professional fitter, joiner or builder to measure up. You can always call us on 01530 273365 or 0844 692 3828 and we will gladly help and advise.

Please remember:

How to measure a double glazed door

Width

The width should be measured brick to brick at three points - top, middle and bottom of the opening. The smallest of these measurements is taken as the width. Always deduct 10mm from the final width.

how to measure the width of a upvc door and frame
Height

The height should be measured brick to brick at three points - left, middle and right of the opening. The smallest of these measurements is taken as the height. Always deduct 10mm from the final height.

how to measure the height of a upvc door and frame

How to measure a double glazed door with side panels or top light

Side Panels

The width should be measured brick to brick at three points - top, middle and bottom of the opening. The smallest of these measurements is taken as the width. Always deduct 10mm from the final width.

The side panel width should be measured from the centre point of the frame between the door and the side panel, to the outer edge of the side panel frame.

how to measure the width of a upvc door with side panels
Top Lights

The height should be measured brick to brick at three points - left, middle and right of the opening. The smallest of these measurements is taken as the height. Always deduct 10mm from the final height.

The top light depth should be measured from the centre point of the frame between the door and the top light to the top of the door frame. This will give you the transom drop for the top light.

how to measure the height of a upvc door and top light

How to measure a double glazed window and frame

Width

The width should be measured brick to brick at three points - top, middle and bottom of the opening. The smallest of these measurements is taken as the width. Always deduct 10mm from the final width.

how to measure the width of a upvc double glazed window
Height

The height should be measured brick to brick at three points - left, middle and right of the opening. The smallest of these measurements is taken as the height. Always deduct 10mm from the final height.

how to measure the height of a upvc double glazed window

How to measure a double glazed square bay and angled bow window

Bay Window

Square Bay windows consist of three sides and two 90 degree corner posts. The width (back span) will need to be measured internally from the existing frame edge to edge. Measure each side window internally and ensure they are the same from one edge of the frame to the other. The height will need to be measured externally brick to brick including any existing cill.

We will add 140mm to the external size for the two 90 degree corner posts which are 70mm square. For example, if the internal width is 1800mm the external width including two 70mm corner posts will be 1940mm, see image.

how to measure a upvc double glazed bay window
Bow Window

Bow windows are slightly more complicated than bays, consisting of two or more sides and shallower angles. The width (back span) will need to be measured internally from the existing frame edge to edge. Measure each individual window facet internally from one edge of the frame to the other. The projection of the bow will need to be measured internally from the inside back span of the window to the inside point of the window frame as below. The height will need to be measured externally brick to brick including any existing cill.

how to measure a upvc double glazed bow window