United Kingdom calculator
Window Replacement Cost Calculator
Estimate the cost to replace your windows in the UK. Adjust the number of windows, their size, frame and glazing, and whether you choose full-frame or insert replacement to see an itemised low–high range for your project.
How this calculator is built
Unit costs with sources
This model cites 3 sources across line-item unit costs, regional labor data, and tax references.
Regional labor adjustment
The region table applies local labor indexes only to labor-heavy line items.
Published methodology
The methodology page lists the formula, size drivers, labor model, and source links.
Estimate your project
Change the default inputs to match your scope. The breakdown updates by line item.
Window Replacement Cost by region: typical ranges
Each range applies that region's labor index to the labor-share line items of the default project; materials stay at national prices. Select a region for its full local breakdown and calculator.
| Region | Typical range | Labor index | Permit |
|---|---|---|---|
| East Midlands | £8,989–£13,483 | 95% | Likely |
| East of England | £8,989–£13,483 | 95% | Likely |
| London | £9,696–£14,544 | 112% | Likely |
| North East | £8,989–£13,483 | 95% | Likely |
| North West | £9,030–£13,546 | 96% | Likely |
| Scotland | £9,197–£13,795 | 100% | Likely |
| South East | £9,363–£14,045 | 104% | Likely |
| South West | £9,654–£14,481 | 111% | Likely |
| Wales | £9,114–£13,670 | 98% | Likely |
| West Midlands | £8,989–£13,483 | 95% | Likely |
| Yorkshire and the Humber | £8,947–£13,421 | 94% | Likely |
Common questions
How much does it cost to replace windows in the UK?
Checkatrade puts the average cost of new double glazing for a typical 3-bed house at £8,000–£15,000, usually for 8–12 windows — roughly £1,000–£1,250 per window installed for standard uPVC casements. Those consumer figures are VAT-inclusive; our calculator works from ex-VAT trade costs and then adds the standard 20% VAT on top, so the headline total is the real bill you pay. Larger bay or bow windows, premium frames, and full-frame replacement push the total higher.
What's the difference between insert and full-frame replacement?
An insert (retrofit) window fits inside the existing frame and is faster and cheaper. Full-frame replacement strips the old frame back to the opening, adding removal and trim labour, and is the right choice when the existing frame is rotten or you're changing the window size. Toggle 'Full-frame replacement' to include that extra labour.
Do I need FENSA or building-control sign-off for new windows?
In England and Wales replacement windows must meet Building Regulations (energy efficiency and, on certain windows, fire escape and ventilation). Most installers self-certify through a competent-person scheme such as FENSA or CERTASS, which avoids a separate building-control application. Scotland operates a separate building-standards regime where like-for-like replacement is often exempt — check with your local council.