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How Much Does a Kitchen Extension Cost in the UK?
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Kitchen Extension Cost intro
How Much Does a Kitchen Extension Cost in the UK?
A kitchen extension can transform both the size and the way a home is used.
Unlike a basic room extension, however, the budget needs to cover more than the construction of the additional floor area.
A kitchen extension may also involve:
- New kitchen units
- Worktops
- Appliances
- Plumbing
- Electrical work
- Heating
- Extraction
- Lighting
- Flooring
- Large glazed doors
- Structural alterations
- Internal remodelling
For 2026, a completed kitchen extension commonly falls somewhere around £40,000–£70,000, with an average project around £50,000, although a small straightforward project may start nearer £20,000 and larger high-specification projects can exceed £100,000.
Another useful way to budget is to separate the extension construction from the kitchen itself. Current UK guidance suggests that adding a kitchen can introduce roughly £15,000–£35,000 of additional cost compared with a standard room extension, depending on the kitchen, services and specification. Checkatrade
At Tholos Architects, we help homeowners consider the extension, kitchen layout, structure and available budget together rather than treating them as separate decisions.
Kitchen Extension Cost explained
Kitchen Extension Cost per Square Metre
Cost per square metre can provide an early budgeting guide, but kitchen extensions are particularly difficult to price using floor area alone.
Current 2026 UK guidance for kitchen-diner extensions gives approximately:
- £1,500–£2,000 per m² for the extension construction, excluding VAT
- Around £1,750 per m² as an average
- Professional fees potentially adding approximately 10–15% depending on the project and appointments required
However, those figures should not be confused with the complete cost of a finished kitchen extension.
The kitchen itself, appliances, premium glazing, structural alterations and finishes can substantially increase the total.
Typical Kitchen Extension Costs
As an early guide:
| Project | Indicative Cost |
|---|---|
| Small/basic kitchen extension | From around £20,000 |
| Typical completed kitchen extension | £40,000–£70,000 |
| Average completed project | Around £50,000 |
| Higher-specification kitchen extension | £70,000–£100,000+ |
| Large/bespoke project | £100,000+ |
Current UK cost guidance places most completed kitchen extensions around £40,000–£70,000, although location and specification can move projects significantly outside this range.
Why Kitchen Extensions Cost More Than Standard Extensions
A standard extension creates additional building space.
A kitchen extension usually creates the building and one of the most technically demanding rooms in the house.
Additional costs may include:
- Kitchen cabinetry
- Worktops
- Appliances
- Plumbing
- Gas where applicable
- Electrical circuits
- Extraction
- Heating
- Lighting
- Flooring
- Tiling
- Decoration
Current cost guidance suggests allowing approximately £15,000–£35,000 more for a kitchen extension than for an equivalent standard room extension because of these additional requirements.
What Is Included in a Kitchen Extension Cost?
This varies considerably between estimates and builder quotations.
The construction element may include:
- Groundworks
- Foundations
- Walls
- Structure
- Roof
- Insulation
- Windows and doors
- Plumbing
- Electrical work
- Plastering
- Basic flooring
- Decoration
Some kitchen-extension quotations may also include installation of the kitchen, although units, worktops and appliances can still be separate.
Always check what the figure actually includes.
What May Not Be Included?
Potential exclusions include:
- Kitchen units
- Worktops
- Appliances
- Specialist lighting
- Premium flooring
- Large glazed doors
- Architectural fees
- Structural engineer
- Planning fees
- Building Control
- Party-wall costs
- Landscaping
- External works
Two quotations can therefore appear dramatically different even when the builders’ underlying labour rates are similar.
How Much Does the Kitchen Itself Cost?
The kitchen specification can change the project budget enormously.
Current 2026 UK data puts a budget kitchen renovation broadly around £6,200–£16,800, while bespoke kitchen renovations can range from approximately £15,000–£50,000. Checkatrade
For a kitchen extension, the kitchen component might therefore range from relatively modest standard units to a substantial bespoke installation.
Kitchen Units
Kitchen cabinetry can range from:
- Standard modular units
- Mid-range fitted kitchens
- Premium branded kitchens
- Bespoke joinery
The layout also affects cost.
A long run of standard cabinets will normally cost less than a design containing:
- Large island
- Pantry cabinetry
- Tall units
- Integrated seating
- Bespoke storage
Worktop Costs
Worktops may include:
- Laminate
- Timber
- Composite
- Granite
- Quartz
- Porcelain
- Natural stone
Premium materials can substantially increase both supply and installation costs.
The size and complexity of a kitchen island can also have a significant effect.
Appliances
Appliances are frequently underestimated during early budgeting.
Potential costs include:
- Oven
- Hob
- Extractor
- Fridge freezer
- Dishwasher
- Wine cooler
- Microwave
- Coffee machine
Premium integrated appliances can add many thousands of pounds to the project.
Kitchen Installation Cost
Kitchen installation should be distinguished from kitchen supply.
Current 2026 guidance gives an average kitchen fitting cost of around £3,500, with a broad range of approximately £2,000–£6,000 for an average family kitchen. Checkatrade
More complex kitchens can cost more to install.
Plumbing Costs
A kitchen extension may require:
- Hot and cold-water supplies
- Sink waste
- Dishwasher connection
- Washing machine connection
- External tap
- Boiler alterations
Costs generally increase when the kitchen moves a significant distance from existing services.
Kitchen Extension Cost
Keep the Kitchen Near Existing Services Where Possible
One way to control cost is to consider the location of:
- Water
- Waste
- Gas where applicable
- Boiler
- Existing drainage
Moving everything across the house is possible, but it can increase both cost and construction complexity.
Good kitchen planning should consider services early.
Electrical Costs
Modern kitchens can require a substantial electrical installation.
This may include:
- Appliance circuits
- Sockets
- Island power
- Lighting
- Extractor
- Induction hob
- Oven
- Integrated appliances
- USB/data points
The more sophisticated the kitchen specification, the more important it becomes to plan the electrical layout before construction.
Kitchen Lighting
Lighting can include:
- Ceiling lighting
- Pendant lighting
- Under-cabinet lighting
- Feature lighting
- Island lighting
- External lighting
Architectural lighting schemes can add considerable cost compared with a simple installation.
Heating
The extension may require:
- New radiators
- Underfloor heating
- Heating controls
- Boiler assessment
Large open-plan spaces may require a different heating strategy from the original rooms.
Underfloor Heating
Underfloor heating is popular in kitchen extensions because it avoids placing radiators on valuable wall space.
The cost depends on:
- Floor area
- Heating system
- Floor construction
- Controls
It should be designed into the project early because it affects floor build-ups and services.
Structural Alterations
Many kitchen extensions involve removing part or all of the existing rear wall.
This can require:
- Structural steel
- Columns
- Padstones
- Temporary support
- New foundations
The larger the opening, the more substantial the structural solution may become.
A small extension with a very large opening into the existing house can therefore cost considerably more than its floor area suggests.
kitchen extension cost
Open-plan Kitchen Extension Cost
Creating an open-plan kitchen often involves work well beyond the new extension.
You may also need to alter:
- Existing dining room
- Existing kitchen
- Hallway
- Utility space
- Internal walls
This internal remodelling increases the project budget without increasing the extension’s square metres.
Kitchen-diner Extension Cost
Kitchen-diner extensions are one of the most popular layouts.
Current UK guidance gives a typical construction cost of around £1,500–£2,000 per m² excluding VAT, with a 20 m² basic kitchen-diner extension around £30,000–£40,000 before professional fees and the wider kitchen specification are considered. Checkatrade
The complete project may cost considerably more once you include:
- Kitchen
- Appliances
- Glazing
- Finishes
- Professional costs
Rear Kitchen Extension Cost
A rear kitchen extension may create:
- Larger kitchen
- Kitchen-diner
- Family space
- Better connection to the garden
The project cost can increase significantly where the design includes:
- Large rear opening
- Sliding doors
- Rooflights
- New kitchen
- Internal remodelling
Side-return Kitchen Extension Cost
Side-return extensions are particularly popular for kitchens in Victorian and Edwardian houses.
They can transform a narrow rear layout without adding a huge amount of floor area.
However, the cost per square metre can be relatively high because the project may involve:
- Structural work
- Drainage
- Roof glazing
- Boundary construction
- Full kitchen replacement
Current UK guidance puts side-return extensions broadly around £30,000–£65,000, while side-return construction can vary from approximately £1,500–£4,500 per m² depending on the project.
Wraparound Kitchen Extension Cost
A wraparound extension combines rear and side extension space.
This can create enough room for:
- Large kitchen
- Island
- Dining area
- Family space
- Utility room
But it can also require:
- More foundations
- More structural work
- Complex roof junctions
- Drainage changes
- Significant internal remodelling
Single-storey Kitchen Extension Cost
Most kitchen extensions are single-storey projects.
A broad 2026 starting point for single-storey extension construction is around £1,800–£3,000 per m², depending on complexity and specification.
The kitchen, glazing and internal work then need to be considered on top of the base construction budget.
Large Sliding Doors and Bifold Doors
Large glazed openings are popular in kitchen extensions.
But they can affect both:
- Glazing cost
- Structural cost
Current guidance suggests allowing around £5,000 for bifold doors as part of a kitchen-extension project, although size, material and specification can move the price considerably.
Very large sliding or bespoke glazed systems can cost significantly more.
Rooflights
Rooflights can improve daylight where the extension makes the original house deeper.
Cost varies depending on:
- Size
- Number
- Brand
- Fixed or opening
- Electric operation
- Installation
Standard rooflights generally cost less than large bespoke roof glazing.
Roof Lanterns
Roof lanterns can become a significant design feature.
They can also add:
- Structural work
- Glazing cost
- Installation cost
- Fixed or opening
- Electric operation
- Installation
They should therefore be considered within the budget early rather than added late in the project.
kitchen extension cost
Flooring
Kitchen flooring needs to cope with heavy everyday use.
Options may include:
- Porcelain tiles
- Engineered timber
- Luxury vinyl
- Natural stone
The floor specification can materially affect cost across a large open-plan area.
Decoration
Check whether the builder’s quotation includes:
- Preparation
- Painting
- Woodwork
- Decoration to altered existing rooms
The extension may be fully decorated while neighbouring areas affected by the works remain excluded.
Utility Room Costs
Kitchen extensions sometimes also create a separate utility room.
This may add:
- Cabinetry
- Sink
- Plumbing
- Appliances
- Electrical points
- Ventilation
A utility room can improve the overall layout, but it should be included in the budget rather than treated as free additional space.
Pantry and Bespoke Storage
Large kitchen extensions often include:
- Pantry
- Larder
- Full-height cabinetry
- Built-in seating
- Bespoke storage
These can add significant joinery costs, particularly when custom-made.
Moving the Existing Kitchen
Sometimes the extension does not simply enlarge the existing kitchen.
The kitchen moves completely.
This can require:
- Removing old units
- New services
- New drainage
- Making good
- Redecoration
The existing kitchen area may then become:
- Utility
- Dining room
- Office
- Circulation space
All of this needs to be included in the project budget.
Drainage Costs
Kitchen extensions frequently interact with existing drainage.
Work may involve:
- Moving manholes
- Rerouting drains
- New kitchen waste
- Rainwater drainage
Drainage should be investigated before construction where possible.
Foundations
Foundation costs depend on:
- Ground conditions
- Trees
- Existing drains
- Access
- Foundation depth
Unexpected conditions below ground can increase the construction cost.
Difficult Access
Access can have a significant effect on cost.
Examples include:
- Terraced properties
- No side access
- Materials carried through the house
- Restricted parking
- Limited machinery access
The same kitchen extension can therefore cost more on one property than another.
Regional Differences
Construction prices vary around the UK.
London and the South East are generally more expensive.
Current 2026 guidance suggests a typical kitchen extension in London and the South East may fall around £55,000–£90,000, compared with a national typical range of £40,000–£70,000.
kitchen Extension cost
Planning Permission Costs
Some kitchen extensions require planning permission.
Others may fall within permitted development rights depending on:
- Size
- Height
- Position
- Property type
- Previous alterations
- Location
Potential planning costs should be included in the overall budget.
Building Regulations Costs
Kitchen extensions generally need to comply with applicable Building Regulations.
Requirements may cover:
- Structure
- Insulation
- Ventilation
- Drainage
- Electrical work
- Fire safety
- Glazing
Structural Engineer Costs
A structural engineer may be required where the project includes:
- Removal of load-bearing walls
- Large openings
- Steel beams
- Columns
- Complex roof arrangements
Engineering fees should be considered separately from the builder’s construction cost unless specifically included.
Professional Fees
The overall budget may also need to include:
- Architectural services
- Structural engineer
- Building Control
- Party-wall surveyor
- Other specialists
Professional fees are not normally included in generic construction cost-per-square-metre figures.
Party Wall Costs
Depending on the extension’s position and excavation, the Party Wall etc. Act 1996 may apply.
Where surveyors are required, their fees should be added to the overall project budget.
VAT
Always check whether VAT is included.
This applies to:
- Cost guides
- Builder quotations
- Kitchen quotations
- Specialist suppliers
A quote that excludes VAT can appear substantially cheaper than the final amount payable.
Allow for Contingency
A kitchen extension should have some financial contingency.
Around 10–15% of the construction budget is a useful early starting point for many projects.
A larger allowance may be sensible for:
- Older houses
- Projects involving substantial structural alteration
- Properties where existing construction is uncertain
kitchen Extension cost
Can I Build a Kitchen Extension for £30,000?
Possibly, but it would generally need to be:
- Small
- Straightforward
- Modestly specified
- Structurally simple
Current 2026 guidance puts an average kitchen extension around £30,000 in some basic scenarios, but more complete kitchen-extension projects commonly sit substantially higher once kitchen fittings and services are included.
Can I Build a Kitchen Extension for £50,000?
Yes, £50,000 sits around the current average for a completed kitchen extension nationally.
What it buys depends on:
- Extension size
- Kitchen specification
- Location
- Glazing
- Structural work
A £50,000 budget should still be carefully planned.
Can I Build a Kitchen Extension for £75,000?
A £75,000 budget provides considerably more flexibility.
Depending on the project, it may support:
- Larger extension
- Better kitchen
- Larger glazing
- Structural remodelling
- Higher-quality finishes
But premium kitchens and bespoke glazing can still push the total higher.
Can I Build a Kitchen Extension for £100,000?
A £100,000 budget can support a substantial kitchen-extension project in many parts of the UK.
However, large high-specification projects containing:
- Bespoke kitchen
- Premium appliances
- Large structural glazing
- Extensive internal remodelling
- Custom joinery
can exceed £100,000 relatively easily.
How to Reduce Kitchen Extension Costs
Cost control is most effective during design.
Potential savings include:
- Keep the footprint efficient
- Use a simple roof
- Avoid unnecessarily large structural spans
- Keep services near existing locations
- Use standard glazing sizes
- Limit bespoke cabinetry
- Separate essential items from optional upgrades
- Avoid unnecessary floor area
The aim should be to simplify the project rather than compromise important construction quality.
Design the Kitchen Before Finalising the Extension
The kitchen layout should influence the architecture.
Before fixing the extension dimensions, think about:
- Island size
- Cabinet runs
- Dining table
- Circulation
- Appliances
- Storage
- Doors
- Views
- Lighting
Adding another metre to an extension because the kitchen was not planned properly can be far more expensive than designing the room correctly from the beginning.
kitchen extension cost
Do You Actually Need a Bigger Extension?
Sometimes the answer is not simply more floor area.
A smaller extension combined with:
- Better internal layout
- Removal of an awkward wall
- Better circulation
- More efficient storage
can create a better kitchen for less money.
Get Comparable Builder Quotes
When the project is sufficiently developed, builders should ideally price the same information.
This may include:
- Architectural drawings
- Structural information
- Kitchen layout
- Window and door specification
- Scope of works
Otherwise, one builder may include the kitchen installation while another excludes it completely.
Kitchen Extension Budget Checklist
Your overall budget may need to include:
- Main extension construction
- Structural work
- Kitchen units
- Worktops
- Appliances
- Kitchen installation
- Plumbing
- Electrical work
- Heating
- Extraction
- Lighting
- Windows and doors
- Rooflights
- Flooring
- Decoration
- Utility room
- Architectural fees
- Structural engineer
- Planning
- Building Control
- Party-wall matters
- External works
- VAT
- Contingency
The extension and kitchen should be budgeted together from the start.
How Tholos Can Help Control Kitchen Extension Costs
A successful kitchen extension is not simply the largest space that fits behind the house.
The extension needs to work around:
- Kitchen layout
- Furniture
- Circulation
- Natural light
- Structure
- Existing services
- Connection to the garden
- Available budget
At Tholos Architects, we can develop these elements together so that the design responds to the way the space will actually be used.
That can help avoid unnecessary floor area, complicated structural solutions and expensive changes later in the project.
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– Lawrence Ipsum, Homeowner · London –
Frequently Asked Questions
How much does a kitchen extension cost in the UK?
A completed kitchen extension commonly costs around £40,000–£70,000 in 2026, with an average around £50,000, although high-specification projects can exceed £100,000.
How much does a kitchen extension cost per m²?
Current kitchen-diner extension guidance gives around £1,500–£2,000 per m² excluding VAT for the construction element. The kitchen itself and other project costs need to be considered separately.
How much extra does adding a kitchen cost?
Current UK guidance suggests allowing approximately £15,000–£35,000 extra compared with a standard room extension, depending on the kitchen, plumbing, electrics and other requirements.
Does the cost include kitchen units?
Not necessarily.
Always check whether the figure includes:
- Units
- Worktops
- Appliances
- Installation
How much does kitchen fitting cost?
For an average family kitchen, current guidance suggests approximately £2,000–£6,000, with an average around £3,500 for fitting.
Do kitchen extensions need planning permission?
Not always.
Some can fall within permitted development rights depending on the property and proposal.
Do kitchen extensions need Building Regulations approval?
Applicable Building Regulations requirements generally apply even when planning permission is not needed.
Plan the Kitchen and Extension as One Project
The biggest mistake when budgeting for a kitchen extension is to think only about the cost of constructing the new floor area.
You also need to consider:
- Kitchen
- Appliances
- Services
- Structure
- Glazing
- Internal alterations
- Finishes
For 2026, £40,000–£70,000 is a useful broad starting range for many completed UK kitchen extensions, but the actual cost can move substantially depending on the project.
At Tholos Architects, we can help design the extension and kitchen around the space you need and the budget you actually have.
Disclaimer
This article is part of a series created by our dynamic marketing team for informational purposes only. While we strive to review all content thoroughly, occasional oversights may occur, even after publication. Therefore, we cannot accept liability for any interpretations or use of the information provided. For the most up-to-date information or to report any discrepancies, please contact us at hello@tholos-architects.com.
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