Cost guide
How much does a kitchen extension cost?
What a kitchen extension adds on top of a standard extension, and what a typical project costs in total.
A kitchen extension typically adds £15,000–£35,000 on top of the cost of a standard extension, according to both HomeOwners Alliance and Checkatrade, with a typical 20m² kitchen-diner extension running £30,000–£40,000 in total.
Last updated 17 August 2026
| Range | ||
|---|---|---|
| Added on top of a standard extension | £15,000–£35,000 | Total project |
| Typical 20m² kitchen-diner extension | £30,000–£40,000 | Total project |
Sources: HomeOwners Alliance (2026 guide), Checkatrade (no explicit page date found — figures cross-checked against the general house-extension-cost page, updated June 2026)
Key points
- Kitchen specification and fit-out — units, worktops and appliances are on top of the building cost.
- Whether the project includes an island, which needs the layout and services planned around it from the start.
- The extension configuration behind it — rear, side or wraparound — which follows the same cost drivers as any other extension.
These are general published ranges, not a quote. Get an estimate based on your own project.
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