Kitchen Extension Cost
Small15 m²
About 3 m by 5 m: a galley kitchen widened into a room you can eat in.
£27kto£39k
Medium25 m²
About 4 m by 6.25 m: kitchen, island and a table for six.
£45kto£65k
Large40 m²
About 5 m by 8 m: kitchen, dining and a sofa end across a wide plot.
£72kto£104k
Typical 2026 prices for the building work at a standard to good finish, VAT included. Kitchen units and fees are extra. A guide, not a quote.
Get a quoteWork out your own figure
Set the floor area and the finish. The total adds the two things most price guides leave off: the kitchen and the fees.
Guide price, all in
£77,300to£97,300
- Building work, with VAT
- £55,000 to £65,000
- Kitchen, fitted
- £20,000 to £27,500
- Design, engineer, building control
- £2,300 to £4,800
Typical national ranges for 2026, including VAT. London and the South East usually cost 20 to 40% more. A guide, not a quote.
Get a quoteWhat the money buys
The rate per square metre pays for the room: foundations, walls, roof, the steel over the new opening, doors, rooflights, electrics, heating, plaster and floor.
The kitchen is a separate order, and so are the drawings, the engineer and building control. When two quotes sit far apart, compare what each leaves out before the totals.
Cost per m² by finish
Typical national rates for a single-storey kitchen extension in 2026, including VAT. London and the South East usually cost 20 to 40% more.
| Finish | Per m², with VAT | 25 m², with VAT |
|---|---|---|
| StandardBrick and block, flat roof with one rooflight, uPVC or basic aluminium doors, plastered and painted | £1,800 to £2,200 | £45,000 to £55,000 |
| GoodAluminium sliding or bifold doors, two or three rooflights, underfloor heating, better floor finish | £2,200 to £2,600 | £55,000 to £65,000 |
| HighStructural glazing, slim-frame doors, bespoke joinery, stone or polished concrete floor | £2,600 to £3,000 | £65,000 to £75,000 |
Where these figures come from
From budget to build
Fix a budget
Use the calculator, then hold back a tenth for what the ground reveals.
Drawings and consent
Check permitted development first. A householder planning application usually takes about eight weeks.
Like-for-like prices
Ask each builder to price the same drawings and the same list of inclusions.
Build
Expect 10 to 16 weeks on site. The old kitchen usually works until the wall comes through.
Costs by type of job
- Rear extension cost
The straight extension across the back of the house, by depth and width.
- Side return extension cost
Filling the alley beside a Victorian or Edwardian kitchen.
- Small kitchen extension cost
Jobs under 15 m², and why they cost more per square metre.
- Kitchen diner extension cost
Knocking through and extending to make one family room.
Kitchen extension costs, answered
How much does a kitchen extension cost in 2026?
For the building work alone, about £27,000 to £39,000 for 15 m², £45,000 to £65,000 for 25 m² and £72,000 to £104,000 for 40 m², with VAT, at a standard to good finish. The kitchen and the fees are on top.
Do I pay VAT on a kitchen extension?
Yes, at the standard 20% rate, on labour and materials. Every total on this site includes it.
Do I need planning permission?
Often not. In England a single-storey rear extension up to 3 m deep on a terraced or semi-detached house, or 4 m on a detached one, is usually permitted development. Scotland has its own limits, and every extension there needs a building warrant.
Get a quote for your kitchen extension
Your postcode, four quick questions about the job, then how to reach you. It takes about a minute.
This is a free introduction service, not a building firm. We find an extension builder who works in your area and tell you who they are. Your details go to them only when you say yes.
Thanks. We have your enquiry.
- We look for an extension builder who takes on kitchen extensions in your postcode area, then email or phone you with the firm's name.
- Nothing is passed on until you tell us to go ahead.
- The builder visits, measures up and prices the work. We will not send you marketing.