How to Price a Kitchen Extension in 2026

Pricing a kitchen extension is one of the most common — and most mispriced — jobs in UK residential construction. Get it wrong and you either lose the job or lose your margin. Here's how to get it right.

Start with the scope

Before you touch a calculator, nail down the scope with your client. A kitchen extension can mean anything from a simple 3m rear extension to a full-width wrap-around with structural steel, underfloor heating, and bi-fold doors.

Key questions to ask:

Size: What's the footprint in square metres?
Structural work: Is steel required? Party wall implications?
Services: Gas, electric, plumbing — are they moving or extending?
Finish level: Builder's finish, mid-range, or high-end?
Kitchen supply: Are you fitting the kitchen or just the shell?

Material cost benchmarks (2026)

Here are ballpark material costs per square metre for a standard rear kitchen extension in London and the South East:

| Category | Cost per m² | |----------|-------------| | Foundations | £180–£250 | | Blockwork & brickwork | £120–£180 | | Roof (flat, EPDM) | £90–£130 | | Structural steel | £60–£100 | | Windows & doors | £150–£300 | | First fix (electrics, plumbing) | £80–£120 | | Plastering & second fix | £60–£90 | | Flooring | £40–£80 |

Total materials: roughly £780–£1,250 per m² depending on specification.

Labour and your rate

Most builders undercharge on labour. Your day rate should reflect your experience, your overheads, and the going rate in your area.

A realistic labour rate for a skilled builder in London (2026) is £250–£350 per day. For a two-person team on a 4-week kitchen extension, that's:

2 people × 20 days × £300 = £12,000 labour

Don't forget subcontractors: electricians, plumbers, plasterers, and roofers will add to this.

Margin and contingency

Apply your margin on top of costs, not rolled into them. A healthy margin for residential work is 15–25%. On top of that, add a 5–10% contingency for unknowns — because there are always unknowns.

Common pricing mistakes

Forgetting prelims: Skip hire, scaffolding, building control fees, and temporary works all cost real money.
Underquoting to win work: A job that loses money is worse than no job at all.
Not itemising: Lump-sum quotes make it harder to manage variations. Break it down.
Ignoring the programme: A 6-week job that drags to 10 weeks eats your margin in overhead.

Use QuoteLab to price smarter

QuoteLab helps you build detailed, professional quotes in minutes. Track your win rate, see which jobs are most profitable, and stop leaving money on the table.