New Windows Installation Cost Calculator

How this calculator works

This calculator estimates a realistic price range rather than a single figure, because real-world quotes genuinely vary that much. It starts from typical UK supplied-and-fitted price ranges drawn from published 2026 industry cost guides, then multiplies them by the number of units you enter and by adjustment factors for each choice you make below. The result is a low-to-high band that a fair quote is likely to fall within, not a promise of the exact price you will pay.

New window prices in the UK in 2026 typically run from around to per standard double glazed uPVC window supplied and fitted, with a full house replacement of 8 to 12 windows commonly landing between and . Premium materials, large openings, sash styles and bay windows all push the total higher, while simple like-for-like casement swaps on an accessible modern property sit at the lower end.

Number of windows

Enter the total number of windows you want installed or replaced. Most UK three bedroom houses have 8 to 12 windows, while flats and bungalows often have 4 to 8. Replacing several windows in one visit usually works out cheaper per window than doing them one at a time, because the installer only sets up, travels and scaffolds once.

Window size

Size is one of the biggest cost drivers for any glazed unit. A larger opening needs more frame material and a bigger, heavier sealed glass unit, and it usually takes longer to fit. The calculator uses three broad size bands based on common UK window dimensions: choosing the small band reduces the typical range by around 20 percent, while the large band increases it by around 40 percent. If your windows vary in size, run the calculator once per size band and add the results together.

Frame material

Frame material has a bigger effect on price than almost any other choice. uPVC is the baseline and accounts for around three quarters of UK installations. Aluminium typically costs 1.5 to 2 times as much as uPVC for the same opening, in exchange for slimmer sightlines and a longer lifespan. Timber usually costs around twice as much as uPVC and suits period properties, but needs repainting every five to eight years. Composite frames, with a timber core and aluminium outer skin, sit at the top of the market.

Specification level

Two windows that look similar from the street can sit at very different price points. Budget products use simpler profiles, standard hardware and basic glass. Mid-range covers the typical A-rated units most UK installers quote by default. Premium covers high-end systems with upgraded security hardware, better thermal performance, special finishes or designer profiles, and typically adds around 30 percent to the price.

Where you live

Labour rates are not uniform across the UK. Published cost guides consistently show installation prices in London and the South East running roughly 20 to 30 percent above the national average, driven by higher labour costs, travel, parking and congestion charges. The calculator applies an uplift of around 20 percent if you select London and the South East. Product prices themselves are broadly similar nationwide, so the difference mostly reflects fitting costs.

What else affects the price

The final quote you receive depends on much more than the number of windows. Frame material is the single biggest driver, with aluminium and timber costing roughly 1.5 to 2 times the equivalent uPVC unit. Window style matters too: sash windows typically cost 50 to 80 percent more than casements because of their sliding mechanism, and bay or bow windows cost several times a flat window. Access is a hidden cost many people forget, since upper floor windows that cannot be fitted from inside can add around to of scaffolding to a project. Finally, coloured or woodgrain finishes typically add 20 to 40 percent over standard white.

Planning permission, building regulations and certification

Like-for-like window replacement on most houses does not need planning permission, but listed buildings always require consent and conservation areas often restrict materials and styles on visible elevations, so check with your local planning authority if either applies. Building regulations apply to every replacement window in a dwelling, setting minimum energy performance and safety glazing standards. Installers registered with a competent person scheme, such as FENSA or Certass, can self-certify compliance and issue a certificate after completion; otherwise you must arrange building control sign-off separately. Keep the certificate safe, as buyers’ solicitors routinely ask for it when you sell.