April 28^th, 2025

If you’re planning to remodel your existing space to make way for an open-plan kitchen diner, the total cost can vary widely depending on factors such as the specification, local labour rates, structural work required, and the quality of materials you choose.

In this article, we cover the costs involved in converting your existing kitchen and living room, typically by downsizing the living space, to create a larger, open-plan kitchen diner. From knocking down walls and moving utilities to choosing your units and finishes, we’ll break down what you can expect to spend.

We’ll take a look at the cost of converting a kitchen diner by region, covering London, North England, Scotland, Wales, and Northern Ireland. We’ll also review average costs per square metre to help you budget accurately and avoid overspending.

Kitchen Diner Cost Calculations

The calculations in this guide assume that the existing structure remains in place, with no additional extensions. The cost breakdown includes a full kitchen remodel with all-new appliances—hob, electric oven, fridge, freezer, dishwasher, washing machine, and extractor fan.

It also includes the installation of bifold doors to open up the space between inside and outside for a blended dining experience.

In terms of build specification, BuildPartner gives you three broad options to choose from:

• Basic spec is a basic finish; e.g., Leyland, Everest, Wickes.
• Standard spec is a standard finish; e.g., Dulux, Hamilton, Slim Line.
• Premium spec is a high-spec finish; e.g., Farrow & Ball, Fine Line, Siemens.

In this article, we’ve provided a breakdown of the cost of converting to a kitchen diner for all three specifications. In addition to this, we have also provided three different benchmarks to show the range of pricing you can expect among different contractors. These are:

• Low benchmark – smaller companies are generally lower cost but less specialised and with low project management function; good for low/mid-spec projects and tight budgets.
• Mid benchmark – medium-sized companies offer a balanced mix of cost-effectiveness and specialisation; good for mid-range projects for effective execution within moderate budgets.
• High benchmark – larger companies generally have a higher cost base but can handle a wide variety of specialist tasks; good for mid/high-spec projects and project management.

Cost Of Kitchen Diner Conversion (Basic Spec)

Below is a table showing the average cost of converting a kitchen diner in the UK to a basic spec:

Kitchen Diner Conversion (Basic Spec)	Total Average Build Cost			Average Cost Per Sq Metre
	Low Benchmark	Mid Benchmark	High Benchmark	Low Benchmark	Mid Benchmark	High Benchmark
East Anglia	£25,792	£28,840	£31,654	£614	£687	£754
Greater London	£27,470	£32,271	£34,396	£654	£768	£819
Inner London	£28,390	£31,780	£33,296	£676	£757	£793
Midlands	£25,026	£27,983	£30,714	£596	£666	£731
North England	£24,598	£27,505	£30,189	£586	£655	£719
Northern Ireland	£25,722	£27,934	£31,425	£610	£665	£748
Scotland	£25,839	£28,892	£31,711	£615	£688	£755
South East	£25,169	£28,108	£31,225	£651	£727	£799
South West	£25,301	£29,056	£31,900	£619	£692	£760
Wales	£24,610	£27,518	£29,602	£586	£655	£705
Average	£25,792	£28,989	£31,611	£621	£696	£758

All costs exclude VAT.        

Here’s what the data shows for the cost of converting a kitchen diner to a basic spec:

• It costs 8% more to convert a kitchen diner in Inner London.
• The minimum cost is £24,598, and the maximum cost is £34,396.
• The total average cost is £28,797, or £692 per square metre.

Start your free trial with BuildPartner to get a bespoke estimate of your construction project within minutes.

Cost Of Kitchen Diner Conversion (Standard Spec)

The table below shows the average cost of converting a kitchen diner in the UK to a standard spec:

 

Kitchen Diner Conversion (Standard Spec)	Total Average Build Cost			Average Cost Per Sq Metre
	Low Benchmark	Mid Benchmark	High Benchmark	Low Benchmark	Mid Benchmark	High Benchmark
East Anglia	£33,824	£37,821	£41,511	£805	£900	£988
Greater London	£35,516	£41,339	£44,519	£846	£984	£1,060
Inner London	£36,787	£41,154	£42,611	£876	£980	£1,015
Midlands	£33,058	£36,964	£40,571	£787	£880	£966
North England	£32,630	£36,486	£40,046	£777	£869	£953
Northern Ireland	£33,754	£36,695	£41,282	£801	£874	£983
Scotland	£33,870	£37,873	£41,568	£806	£902	£990
South East	£32,559	£36,260	£39,958	£843	£938	£1,034
South West	£33,333	£38,037	£41,757	£810	£906	£994
Wales	£32,641	£36,499	£39,094	£777	£869	£931
Average	£33,797	£37,913	£41,292	£813	£910	£991

 All costs exclude VAT.

 

Here’s what the data shows for the cost of converting a kitchen diner to a standard spec:

• The minimum cost is £32,559, and the maximum cost is £44,519.
• The total average cost is £37,667, or £905 per square metre.

Cost Of Kitchen Diner Conversion (Premium Spec)

The table below shows the average cost of converting a kitchen diner in the UK to a premium spec:

Kitchen Diner Conversion (Premium Spec)	Total Average Build Cost			Average Cost Per Sq Metre
	Low Benchmark	Mid Benchmark	High Benchmark	Low Benchmark	Mid Benchmark	High Benchmark
East Anglia	£47,457	£53,066	£58,243	£1,130	£1,263	£1,387
Greater London	£49,136	£57,851	£60,985	£1,170	£1,377	£1,452
Inner London	£51,041	£57,018	£58,475	£1,215	£1,358	£1,392
Midlands	£46,691	£52,209	£57,303	£1,112	£1,243	£1,364
North England	£46,264	£51,731	£56,778	£1,102	£1,232	£1,352
Northern Ireland	£45,338	£50,697	£55,643	£1,079	£1,207	£1,325
Scotland	£47,504	£53,118	£58,300	£1,131	£1,265	£1,388
South East	£45,102	£50,396	£55,954	£1,074	£1,200	£1,332
South West	£46,966	£53,282	£58,489	£1,118	£1,269	£1,393
Wales	£46,275	£51,744	£55,207	£1,102	£1,232	£1,314
Average	£47,177	£53,111	£57,538	£1,123	£1,265	£1,370

All costs exclude VAT.

Here’s what the data shows for the cost of converting a kitchen diner to a premium spec:

• The minimum cost is £45,102, and the maximum cost is £60,985.
• The total average cost is £52,609, or £1,253 per square metre.

 

Average Cost Of Converting A Kitchen Diner

So, how much does it cost to convert to a kitchen diner in the UK? Based on the three specifications covered in this article, you can expect a kitchen diner conversion to cost on average (when using a mid-benchmark contractor):

• Basic spec: £28,989, or £696 per square metre.
• Standard spec: £37,913, or £910 per square metre.
• Premium spec: £53,111, or £1,265 per square metre.

The costs in this guide exclude extensions. If you’re planning to build an extension to increase the floorspace of your kitchen diner, you should factor in approximately £2,900 per square metre for a ground-floor extension, and £2,400 for a double-storey rear extension.

For more specific information about extension costs, check out this article.

Please remember that all costs exclude VAT.

Start your free trial with BuildPartner to get a bespoke estimate of your construction project within minutes.

Frequently Asked Questions About Kitchen Diner Conversions

Here are some frequently asked questions about the costs of converting a kitchen diner.

How long does it take to convert a kitchen diner?

Converting to a kitchen diner takes an average of 3.75 weeks, with an average of two tradespeople carrying out the work. Here’s a rough breakdown of the project:

• Demolitions begin in Week 1 and wrap up by early Week 2.
• Windows and doors are installed in Week 1, followed by internal doors and frames.
• Drainage and pipework start in Week 2, overlapping with heating and cooling.
• Wired appliances are set up in Week 3, alongside ceiling and wall preparation.
• Worktops and kitchen appliances are installed in Week 4.
• Decoration begins in Week 4 and finishes in Week 5, marking the project’s end.

Can I knock through a wall to open up space for a kitchen diner?

Yes, if the wall isn’t load-bearing, it’s usually straightforward. If it’s structural, you’ll need a steel beam (RSJ—rolled steel joist) and Building Regulations approval.

How do I know if a wall is load-bearing?

Here are a few signs that a wall might be load-bearing:

• It feels solid (brick or block rather than stud and plasterboard).
• It’s located in the centre of the house, supporting joists or beams above.
• It runs perpendicular to floor joists.
• There’s another wall or beam directly above it on the upper floor.
• It aligns with beams or support structures in the loft or basement.

The only reliable way to be sure is to consult an experienced builder or structural engineer. They can assess the property’s structure and confirm what support is needed if you plan to remove it.