Compare · Updated June 2026
Kitchen Extension vs Rear Extension: Cost Compared (2026)
A rear extension describes the structure (a single-storey build off the back of the house); a kitchen extension is a rear extension that happens to house a new kitchen. So the shell costs the same — roughly £2,000–£3,000/m² in 2026 — and the real cost gap is the kitchen fit-out, which adds £8,000–£30,000+ depending on units, worktops and appliances. This guide compares the two line by line so you can budget accurately and decide which adds more value to your home.
Cost per m² Shell vs fit-out Resale value
Side by Side
Kitchen Extension vs Rear Extension (2026)
Typical single-storey build, 20 m², standard spec, England & Wales.
Which to Choose
Which Adds More Value?
- For resale, the fitted kitchen extension wins. A modern open-plan kitchen-diner is the single most requested feature by UK buyers and typically returns 60–80% of its cost at sale, more in higher-value areas.
- For pure floor-space-per-pound, the empty rear extension is cheaper. If you only need a bigger living room or playroom, you skip the £8k–£30k kitchen bill entirely.
- Watch the kitchen spec creep. The shell price is predictable; the kitchen is where budgets blow out. Set the units/worktop/appliance budget before you start.
- Both usually fall under permitted development up to 6m (terraced/semi) or 8m (detached) under the larger-home extension rules — but check before you commit.
Free Quotes
Compare Real Extension Quotes
BestBuilders matches you with up to 3 vetted UK extension builders — get like-for-like quotes for a shell or a full kitchen extension.
Get My 3 Free Extension Quotes
Takes 60 seconds · No spam · No obligation
Frequently Asked
Common Questions
Only by the cost of the kitchen itself. The building shell costs the same — £2,000–£3,000/m². A kitchen extension adds £8,000–£30,000+ for units, worktops, appliances and plumbing on top.
A fitted open-plan kitchen-diner extension usually adds the most resale value because it's the feature UK buyers most want. An empty rear extension adds space cheaply but less wow-factor.
Often neither — single-storey rear extensions up to 6m (terraced/semi) or 8m (detached) usually fall under permitted development with prior approval. Conservation areas and listed buildings are exceptions.
A single-storey shell is typically 8–12 weeks. A kitchen extension adds 2–4 weeks for the kitchen fit, plumbing and electrics, so budget 10–16 weeks all-in.
Get at least 3 like-for-like written quotes on the same spec and drawings. Extension prices vary 30–50% between builders for identical work, so comparing fairly is the single biggest money-saver.
Keep Reading
Related Guides
More extension cost and comparison guides.