Bay window cost

A bay window makes a room feel bigger and floods it with light — but it costs more than a flat window of the same width, and it helps to know why. As a typical bay window cost guide, a front brick bay sits in the region of £1,400–£2,800 supplied and fitted, depending on size, the number of facets and the glazing you choose.

A brick bay window on the front of a UK home
A classic brick bay — more frame, more glass and structural work than a flat window.

Why a bay costs more than a flat window

A bay is several windows joined at angles, so it uses more frame and glass than a single flat opening. It also needs corner posts and, on many homes, a structural head to carry the load above the bay while the old frame is out. As a rough rule of thumb, a bay build-up costs in the order of 1.5–1.8× the equivalent run of flat windows once that extra material and support is included.

Bay typeTypical supply & fit
Small three-facet uPVC bay£1,400–£2,000
Standard front bay£1,800–£2,800
Large or two-storey bay£2,800–£4,500+

These are illustrative typical ranges. Structural work, the height of the bay and difficult access all move the figure, so a survey is especially important for bays.

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The front of a UK house with several replacement windows
Bays are often replaced alongside the rest of a frontage for a consistent look.

What changes a bay window estimate

If you are pricing a bay as part of a wider project, it helps to understand the window installation cost that sits behind the fitting, and to compare the bay against the plain-window cost per window so you can see the premium clearly.

New windows viewed from inside a bright living room
A bay transforms the light and space inside a room, which is why it costs more.

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