UK price guide · Updated 26 Sep 2026
Window Prices by Size
Size matters, but it is not the only thing that matters. Two windows with the same overall dimensions can cost differently if one has more separate sections or opening sashes.
Current price examples
These examples come from the same pricing model used by the calculator. They are market estimates rather than binding installer quotations.
Why size alone is not enough
A 1200×1200 window with one opening sash and one fixed pane is not manufactured the same way as a single full-size opener or a more complex top-light arrangement. The number of sections, mullions, transoms and opening sashes all affect cost.
That is why the calculator asks for a rough size and then the closest layout, rather than using a single price-per-square-metre figure.
Useful size inputs
- Rough size is enough for an initial estimate
- Exact width and height tighten the range
- Section count helps price frame complexity
- Opener count and layout affect hardware and fabrication
What “fitted” means here: supply, standard replacement installation and ordinary 20% VAT are included. Unusual access, scaffolding, structural repairs, planning/listed-building requirements and highly bespoke work can sit outside the standard estimate.
Related price guides
Compare closely related products before using the calculator for your exact specification.
Questions people ask
Short answers to the most useful questions around this price topic.
Can I calculate a price without exact measurements?
Yes. Choose small, medium or large and the calculator uses a representative size with a wider uncertainty range.
Does a bigger window always cost more?
Usually, but not always by a simple linear amount. Opening layout and frame design can outweigh a modest size difference.
Are the prices supply only?
No. The guide uses fitted-market pricing including standard installation and VAT.
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