Kitchen Extension Cost: Complete UK Cost Guide for 2026

However, before starting any kitchen extension project, it is important to understand the likely costs involved and set a realistic budget.

If you're also researching broader extension pricing, our guide to house extension cost provides a detailed breakdown of extension costs across Scotland.

How Much Does a Kitchen Extension Cost?

The average kitchen extension cost in the UK typically ranges between £35,000 and £70,000, although larger projects can exceed this. The total cost depends on the extension size, build quality, location, specification and complexity of the building work.

As a rough guide:

Many homeowners ask, "How much does a kitchen extension cost?" The answer depends largely on the floor area, specification and structural requirements. Average kitchen extension costs continue to rise due to labour costs and material costs, making early budgeting essential.

Kitchen Extension Cost Per m²

One of the easiest ways to estimate an extension cost is by calculating the build cost per square metre.

Current UK averages include:

• Single-storey extensions: £1,700–£3,300 per square metre

• Shell construction: £1,800–£3,000 per square metre

• Premium projects: £3,500+ per square metre

In central London and the South East, costs are usually higher than in the North West and Scotland due to increased labour costs and demand.

For example:

A larger floor area typically means more materials, increased labour requirements and a higher overall cost.

Single Storey Kitchen Extension Cost

A single storey extension remains one of the most common ways to create a larger kitchen and dining space.

The typical cost of a single storey kitchen extension ranges between £35,000 and £65,000 depending on size and finish quality.

Factors affecting a single storey extension cost include:

• Ground conditions

• Structural engineer requirements

• Plumbing and electrical work

• Kitchen appliances

• Underfloor heating

• Build quality

• External doors and bifold doors

Simple layouts using standard materials generally offer the most cost-effective solution.

Rear Kitchen Extension Cost

A rear extension is a popular choice for homeowners wanting more room without sacrificing internal living spaces.

The average rear kitchen extension cost falls between £30,000 and £60,000.

Many rear extension projects incorporate:

• Open-plan kitchen diner layouts

• Bi folding doors

• Additional natural light

• Improved access to the garden

• New kitchen installations

Rear extensions are particularly popular because they can often be completed under permitted development rights.

Side Return Kitchen Extension Cost

Side return projects are especially common in Victorian and Edwardian properties.

A side return kitchen extension cost generally ranges between £30,000 and £60,000, depending on the size of the new space and structural complexity.

Although these projects can transform narrow kitchens into spacious kitchen diner extension layouts, complex layouts often increase construction costs.

Kitchen Diner Extension Cost

A kitchen diner extension creates a larger entertaining area while combining cooking and dining space into one functional room.

The average kitchen diner extension cost typically ranges from £40,000 to £70,000.

A kitchen diner can include:

• Large kitchen units

• Custom cabinetry

• Kitchen appliances

• Dining space

• Bifold doors

• Underfloor heating

Many homeowners view a kitchen diner as a worthwhile investment because it creates a dream kitchen while improving everyday family living.

Conservatory Kitchen Extension Cost

A conservatory kitchen extension cost generally ranges between £25,000 and £50,000 depending on specification and structural alterations.

Modern conservatory kitchen extensions often include:

• Insulated roofing systems

• New plumbing connections

• Electrical work

• Open-plan layouts

This type of extension can create significant natural light while maintaining a lower budget than some traditional alternatives.

Orangery Kitchen Extension Cost

An orangery kitchen extension cost typically falls between £35,000 and £70,000.

Orangeries combine traditional masonry construction with extensive glazing, creating bright living spaces that feel connected to the garden.

While more expensive than some standard extension options, they often deliver excellent visual appeal and property value improvements.

What Impacts Kitchen Extension Costs?

Several factors influence the cost of a kitchen extension.

Extension Size

Larger extensions increase expenses due to higher material and labour requirements. More materials and additional structural support naturally increase costs.

Structural Requirements

Complex building work often requires a structural engineer and structural engineer drawings. Site conditions such as poor soil may also require additional foundations.

Build Quality

The finish quality has a major impact on the final budget. Premium finishes, bespoke joinery and custom cabinetry cost substantially more than standard materials.

Fittings and Fixtures

Fitting out the new space often absorbs 30% to 40% of the total cost.

This may include:

• Kitchen units

• Kitchen appliances

• Flooring

• Lighting

• Plumbing

• Electrical work

Location

Projects in central London and the South East usually cost more than comparable projects elsewhere in the UK.

Planning Permission for a Kitchen Extension

Planning permission requirements depend on the size and design of the extension.

Many kitchen extension projects fall under permitted development rights and therefore do not require planning permission.

However, you may require planning permission if:

• The extension exceeds permitted development limits

• Your property is listed

• The property is located in a conservation area

• The design significantly alters the appearance of the house

For many semi detached houses, extensions beyond certain limits may require planning approval from the local council or local authority.

Current planning permission application fees in England are £528, although additional planning-related costs can increase this figure.

You should always confirm requirements before starting a project.

Building Regulations and Building Control

Even when planning permission is not required, building regulations approval is usually necessary.

Building control inspections typically assess:

• Foundations

• Drainage

• Structural work

• Insulation

• Fire safety

• Electrical installations

Building regulations help ensure the extension meets current standards for safety and performance.

Party Wall Agreement Requirements

If your extension affects a shared wall with a neighbouring property, you may need a party wall agreement.

A party wall agreement is particularly common for:

• Semi detached houses

• Terraced properties

• Side return extensions

Failing to obtain the necessary agreement can delay a project and increase costs.

Additional Costs to Budget For

Many homeowners focus only on construction costs and overlook hidden costs.

Common additional costs include:

Professional Fees

Professional fees typically range from 5% to 15% of the overall project budget.

These may include:

• Structural engineer fees

• Architect fees

• Planning consultants

• Surveyors

Plumbing

Upgrading plumbing systems can cost between £500 and £3,000 depending on complexity.

Electrical Work

Electrical work often includes:

• New circuits

• Lighting

• Sockets

• Appliance connections

Kitchen Fitter Costs

A professional kitchen fitter is responsible for installing kitchen units, worktops and appliances.

Kitchen fitter charges vary depending on complexity and specification.

Temporary Kitchen Setup

Many homeowners forget to budget for temporary cooking facilities during the project.

Contingency Fund

Experts generally recommend allocating a contingency fund of 10% to 15% of the budget. Unforeseen structural issues can easily add £5,000 or more to the final cost.

Can a Kitchen Extension Add Value?

A kitchen extension can add significant value to a property.

Research suggests:

• A kitchen extension can increase home value by 5% to 10%

• Well-designed projects may add 10% to 15%

• In some cases, value can increase by more than 15%

Kitchen extensions remain among the most popular home improvements because buyers place significant value on extra space, modern layouts and improved functionality.

For most homeowners, the combination of improved lifestyle and increased property value makes a kitchen extension project a worthwhile investment.

How to Save Money on a Kitchen Extension

There are several ways to save money without compromising build quality.

Use Standard Materials

Standard materials are often significantly cheaper than bespoke alternatives.

Get Three Quotes

Obtaining at least three quotes helps ensure you receive a fair price and allows accurate cost comparisons.

Manage Parts of the Project

Managing selected stages yourself can save 15% to 30% in some circumstances.

Keep the Design Simple

Simple layouts are generally more affordable than complex structural designs.

Phase the Work

Phasing work can help spread costs and improve cash flow.

Set a Realistic Budget

A realistic budget should include:

• Construction costs

• Professional fees

• Fixtures and fittings

• Contingency allowance

Kitchen Extension Cost in Scotland

If you're considering a kitchen extension cost Scotland project, prices are generally lower than those seen in central London and parts of the South East.

For homeowners looking for professional design and construction services, explore our specialist team for house extensions in Scotland.

Homeowners in the west of Scotland can also learn more about our dedicated house extensions in Glasgow service.

Conclusion

The average cost of a kitchen extension in 2026 typically ranges from £35,000 to £70,000, although larger projects can cost considerably more. Planning, professional fees, building regulations, labour costs and finish quality all influence the final extension cost.

Setting a realistic budget, allowing for hidden costs and obtaining multiple quotes will help ensure your project remains on track from start to finish.

If you're exploring alternative ways to create extra space and increase property value, discover our bespoke garden rooms in Scotland for a flexible and cost-effective solution.

FAQs

How much does a kitchen extension cost UK?

Kitchen extension costs in the UK typically range between £35,000 and £70,000, depending on size, specification and location.

What is the average kitchen extension cost?

The average kitchen extension cost is generally between £30,000 and £50,000, although premium projects can exceed this range.

How much does a 20m² kitchen extension cost?

A 20m² kitchen extension typically costs between £40,000 and £66,000 depending on build quality and structural requirements.

Do I need planning permission for a kitchen extension?

Not always. Many projects fall under permitted development rights, although larger extensions may require planning permission.

Is there a kitchen extension cost calculator?

A kitchen extension cost calculator can provide a rough guide, but professional quotations remain the most accurate way to estimate costs.

How much does a small kitchen extension cost?

A small kitchen extension cost typically starts at around £30,000, although final costs vary according to design, location and specification.