uPVC Windows Calculator 2026
Instantly estimate total glazing area, frame perimeter, and window counts for your home improvement or new build project. Plan every room with precision.
Window Specifications
Define your window dimensions, glazing type, and project scope
Total windows across all rooms in the property
Used to estimate typical window configurations
Average size of a single window opening
Affects frame perimeter and sill requirements
Determines glass pane count and insulation rating
Standard uPVC profile depth (typically 60–70mm)
Extra allowance for off-cuts, bay windows, or complex shapes
Window Estimates
Glazing area, frame perimeter & window summary
Enter your window dimensions and project details above, then click Estimate Window Requirements to reveal your complete window specification summary.
Standard uPVC Window Sizes & Glazing Areas
Common uPVC window dimensions and typical glazing areas by room type. Always add 10% wastage for glass cuts and fitting tolerance.
| Window Size (mm) | Glazing Area (m²) | Frame Perimeter (m) | Typical Room |
|---|---|---|---|
| 600 × 600 | 0.36 | 2.40 | Bathroom / WC |
| 900 × 900 | 0.81 | 3.60 | Bedroom (small) |
| 1200 × 1050 | 1.26 | 4.50 | Bedroom / Hall |
| 1800 × 1200 | 2.16 | 6.00 | Living Room |
| 2400 × 1200 | 2.88 | 7.20 | Large Living / Dining |
uPVC Windows FAQ
Answers to the most common questions about uPVC window sizing, glazing types, and planning your window replacement or new-build project.
Standard uPVC windows typically range from 600mm to 1200mm in width and 900mm to 1200mm in height. The most common residential casement window is around 1200mm × 1050mm. Sizes vary by room — bathroom windows are smaller (around 600mm × 600mm) while living room windows can be 1800mm wide or more.
Multiply the width by the height of each window to get its area in square metres, then multiply by the number of identical windows. Sum all window areas to get your total glazing area. Add 10% wastage for cuts and fitting tolerance to ensure you have enough material ordered.
Double glazing uses two panes of glass with an insulating gas cavity, offering good thermal and acoustic performance suitable for most UK homes. Triple glazing adds a third pane for superior insulation, ideal for north-facing elevations or homes in colder climates, though it adds weight and requires stronger frame profiles.
A typical 3-bedroom semi-detached UK house has between 10 and 15 windows including bedroom, living room, kitchen, bathroom, and landing windows. A detached 4-bedroom house may have 16 to 22 windows depending on its design and layout. Flats typically have 4–8 windows.
For standard rectangular window replacements, a 5% wastage allowance on glazing materials is sufficient. For bay windows, bow windows, or bespoke shapes requiring cut glass, allow 10–15% extra to account for off-cuts and fitting adjustments. Always round up to whole units when ordering sealed units.