What a bow window costs in 2026
A bow window curves gently outward from the wall in four, five or six equal sections, where a bay window projects in flat angled panes. Because a bow has more sections and a curved frame, it is the slightly dearer of the two, and like a bay it is priced as one structural unit rather than per pane. The price is driven by the section count: a uPVC bow runs from around £1,250 for a 3-section unit up to about £3,400 for a 6-section one, fully fitted in 2026. The calculator above does not have a separate Bow style, so select Bay as the closest structural match and use the table below to fix on your section count.
As with a bay, half the job is structural: the bow carries load, so the wall above has to be supported while the old unit is removed. That is why the figure sits well above a flat run of casements. Our master double glazing costs page sets these projecting styles against the simpler ones so you can see the gap.
| Bow window (per bow) | uPVC fitted |
|---|---|
| 3 section | £1,250–£1,500 |
| 4 section | £1,650–£2,070 |
| 5 section | £1,950–£2,640 |
| 6 section | £2,340–£3,400 |
Source: MyJobQuote and comparecompanies.co.uk (UK Prices 2026). Aluminium runs roughly 30 to 40% higher and timber roughly 60 to 110% higher for the same bow.
Which frame material suits a bow
uPVC is the value choice and the most common, and it carries the curved structure well. Aluminium suits a contemporary rebuild where slim frames and a large arc of glass matter, priced in the aluminium window calculator. On a period property in a conservation area, timber may be required, costed in the timber window calculator. For the rest of the house, run the simpler openings through the casement window calculator so your whole-house total stays realistic.
The verdict on bow windows
A bow is a handsome period feature and worth keeping, but it is one of the costliest windows on the house and the figure depends heavily on the structure behind it. Price the structural work, not just the glass.
It depends Bow windows: it depends. Worth restoring as a feature, but always price the support and refitting work.
People assume a bow is just a curvier bay, but the extra sections mean more joints, more sealing and a touch more labour, so expect to pay a little more than a bay of the same width. The important thing on either is that the wall above is properly supported while we work. That is where the cost and the quality really sit.
Tom Bradley, FENSA-registered installer
Frequently asked questions
A uPVC bow window costs from £1,250 for a 3-section unit up to around £3,400 for a 6-section one, fully fitted in 2026. Aluminium runs roughly 30 to 40% higher and timber roughly 60 to 110% higher for the same bow.
A bay window projects in flat angled sections, usually three, with sharp corners. A bow window curves outward in four, five or six equal sections to form a gentle arc. A bow has more sections, so it tends to cost a little more than a bay of the same width.
Per whole bow. The price covers the complete curved unit and the structural frame, not each pane. In the calculator, count one bow as a single window and use the table below to match your section count.
Like a bay, a bow projects from the wall and carries load, so it needs corner posts, a head and a base, and the wall above must be supported while the old unit comes out. That structural work, not just the extra glass, is what lifts the price.