Kitchens · Updated 2026
Kitchen extension cost
Typical range£30,000–£120,000· Average kitchen extension + new kitchen (3 bed)
Open-plan kitchen extension costs for 2025 — rear and side return. In the UK, expect to pay between £30,000 and £120,000, with the typical project around £55,000 (average kitchen extension + new kitchen (3 bed)). Regional variation, specification tier and site access conditions all shift the final quote.
Quick answer: Kitchen extension cost in the UK typically costs between £30,000 and £120,000 (Average kitchen extension + new kitchen (3 bed)). London and the South East run 20–35% above this range; the North, Wales and most of Scotland sit 5–15% below.
Homeowners researching this typically also price up new kitchen cost and bifold doors cost. For wider context, browse our bathroom pricing, boiler & heating costs and trades day rates.
Cost table
Indicative price ranges (UK, GBP)
| Item | Typical range (GBP) |
|---|---|
Small rear extension + kitchen (4m x 4m) — 16m² extension, mid-range kitchen | £30,000–£55,000 |
Medium extension + kitchen (4m x 6m) — 24m², open-plan, bifold doors | £50,000–£85,000 |
Side return + rear extension — L-shaped, full open-plan transformation | £55,000–£100,000 |
Premium open-plan (architect designed) — High spec, lantern, feature kitchen | £75,000–£120,000 |
Labour costs
Labour typically accounts for 50% of the total project cost in the UK.
Labour line items
| Item | Typical range (GBP) |
|---|---|
All trades (builder, elec, plumber) | £25,000–£55,000 |
Architect fees | £2,500–£6,000 |
Structural engineer | £800–£2,000 |
Project management | £2,000–£5,000 |
Materials costs
Materials and fittings make up the remainder of the budget, with specification tier driving most of the variation.
Materials & fittings
| Item | Typical range (GBP) |
|---|---|
Extension (structure) | £15,000–£40,000 |
New kitchen (mid-range) | £8,000–£20,000 |
Bifold doors (3.6m) | £3,500–£7,000 |
Roof lantern | £2,500–£8,000 |
Underfloor heating | £2,000–£5,000 |
Factors affecting cost in the UK
- ·Region — London and the South East run 15–30% above national averages.
- ·Specification tier — premium materials and finishes can double the base cost.
- ·Access and site conditions — flats, restricted parking and listed buildings add time.
- ·Scope changes mid-project — late design decisions are the biggest cost overrun driver.
- ·Trade availability — quotes rise 10–20% in peak spring and summer months.
Ways to reduce cost
- ·Stay within permitted development limits (under 3 m for terrace, 4 m for detached) to skip planning.
- ·Choose a single-storey rear rather than wraparound or side return for lowest £/m².
- ·Bundle kitchen + extension into one contract via a design-and-build company.
- ·Specify mid-range glazing rather than minimal-frame structural glass.
- ·Use standard brick or render rather than zinc or timber cladding.
Frequently asked questions
- What is the average cost of a kitchen extension in the UK?
- A kitchen extension typically costs £30,000–£85,000 depending on size and specification, including the extension structure and a new kitchen. London adds 25–35% to these figures.
- Does a kitchen extension need planning permission?
- Many kitchen extensions fall under permitted development if single-storey and extending no more than 3m (semi/terraced) or 4m (detached). The Prior Approval Neighbour Consultation Scheme allows up to 6m/8m. Always verify before starting.
- What is a side return extension?
- In Victorian and Edwardian terraced and semi-detached homes, the side return is the narrow alley alongside the kitchen. Infilling this space (typically 1–1.5m wide) with an extension creates a significantly wider kitchen-diner and is one of the most popular extensions in urban UK.