Kitchen Extension Cost in 2026 — and How to Save on It
31 Oct 2026A kitchen extension is the project almost everyone wants — a bright, open kitchen-diner that opens onto the garden. It's also the easiest extension to overspend on, because the kitchen itself can cost as much as the building work around it.
What a kitchen extension costs in 2026
| Element | Typical 2026 cost |
|---|---|
| Building the extension shell (15–25 m²) | £30,000–£55,000 |
| Kitchen units & worktops (mid-range) | £8,000–£20,000 |
| Appliances | £2,000–£8,000 |
| Bi-fold / sliding doors | £2,000–£8,000 |
| Roof lantern / skylights | £1,500–£5,000 |
| Realistic all-in total | £40,000–£80,000+ |
Where the savings actually are
- Buy the kitchen separately. If a builder supplies the units, they often add a margin. Supplying your own kitchen (and paying them to fit it) can save thousands — just agree clearly who's responsible for what.
- Standard sizes beat bespoke. Off-the-shelf unit sizes and a simple rectangular layout cost far less than a bespoke island with curved ends.
- One roof light instead of a full lantern. You get most of the daylight for a fraction of the glass bill.
- Keep the plumbing where it is. Moving the sink and drains to the far wall means new pipework under a new floor. Keeping services near the existing wall saves labour.
- Sliding doors over bi-folds are often cheaper per metre and let in more glass when closed.
The biggest saving of all
None of the tips above will save you as much as getting the building work competitively quoted. The shell is the biggest line on the invoice, and it's the one with the widest spread between builders. The same kitchen extension can be £35,000 or £50,000 depending purely on which builder you ask — and the only way to know is to ask several.
Get competing quotes for your extension — free
Post your job once on BidsAndMore and vetted local builders bid for it. You compare prices side by side and pick the one that's right — most homeowners find that competition alone knocks thousands off the first number they were quoted.
Post your extension job →FAQ
How much is a small kitchen extension?
A compact single-storey or side-return kitchen extension typically runs £40,000–£60,000 all-in (shell plus a mid-range kitchen) in 2026, more in London.
Can I live in the house during the work?
Usually yes, but expect a few weeks without a usable kitchen. Many people set up a temporary kitchen in another room. Agree the timeline and the "no kitchen" window with your builder up front.
Related: Full house extension cost guide · Replace the whole kitchen, or just the doors? · What a quote's line items are telling you