Cut-to-size helper
Measure from a photo
This helper now lives inside the cut-to-size configurator, on the size step, where a rough size is useful. It gives an estimate from a photo taken next to a sheet of A4 paper; confirm the size on site with a tape before you order, or use the printable measuring pack.
Add a photo
Photograph the opening with a sheet of A4 paper held flat against it, straight-on (not at an angle), the paper is the known reference the maths uses.
JPEG, PNG or WebP, up to 20 MB and 50 megapixels. Your photo stays in your browser, nothing is uploaded anywhere.