Calculate Your Kitchen Extension Cost
2026 Kitchen Extension Cost Guide
| Extension Type | Low/m² | High/m² |
|---|---|---|
| Single Storey Standard | £1,500 | £2,500 |
| Single Storey High-Spec | £2,500 | £3,500 |
| Orangery / Glass Box | £2,000 | £4,000 |
| Two Storey (per floor) | £1,800 | £3,000 |
Frequently Asked Questions
How much does a kitchen extension cost in the UK in 2026?
A single-storey kitchen extension costs £1,500–£3,500 per m² in 2026. A typical 20 m² extension runs £30,000–£70,000 for the build alone. Adding a new kitchen (£8,000–£30,000+) and bi-fold doors (£4,000–£8,000) can push the total past £100,000 in London.
Do I need planning permission for a kitchen extension?
Single-storey rear extensions within Permitted Development limits (4 m for detached, 3 m for semi/terraced) do not require planning permission. Larger extensions and two-storey additions need full planning — the application fee in England is £206.
How much does a new kitchen cost in 2026?
A new fitted kitchen costs £8,000–£12,000 for a budget option, £12,000–£20,000 for mid-range, and £20,000–£50,000+ for bespoke premium kitchens. These prices include supply, fitting and standard appliances. Worktop material, appliance brands and cabinet quality are the main cost drivers.
How much do bi-fold doors cost for a kitchen extension?
Bi-fold or sliding aluminium doors for a 3 m opening cost £4,000–£8,000 supplied and installed in 2026. A 4 m opening runs £6,000–£10,000, and a 6 m opening £9,000–£15,000. The structural steel lintel needed above the opening adds a further £500–£1,500.
How much value does a kitchen extension add to a house?
A well-designed kitchen extension typically adds 5–15% to property value. A £50,000 extension in London could add £75,000–£100,000 to the sale price. The open-plan kitchen-diner with garden access via bi-fold doors is the most sought-after configuration in the UK market.