What’s the average build cost per m² in 2025?

Building a new home or extension is an exciting project that brings plenty of benefits. But one of the first questions people want to know is how much it will cost.

Understanding the average build cost per m² is a crucial step in planning and budgeting for the work. It’ll help you make informed decisions, avoid unexpected expenses, and stay on track financially.

Read on to discover average building costs per square metre, typical costs for common projects, and the key factors that influence the cost.

Average build costs per m² in the UK

In the UK, the average building cost per square metre is between £1,775 - £3,000.

If you prefer using imperial measurements, this translates to an approximate building cost per square foot of between £165 - £280.

The prices in the table do not include VAT. For new builds, VAT is zero-rated.

Factors that affect building costs per square metre

The costs provided are broad estimates to help budget for your project and determine whether you’re being quoted a fair price for the work.

That said, there are generally three key aspects that will impact build costs per m²:

1. Location and labour rates

• Building costs tend to be higher in London and the South East compared to the rest of the UK
• You may find smaller building firms have lower overheads and can therefore offer you competitive rates

2. Design complexity

• Building costs will vary depending on the size and layout of the property, the complexity/difficulty of the design and build, and the time required
• Bespoke or intricate design features will often require experienced specialists who command higher prices

3. Material finishes

• High-specification builds will cost significantly more than those using more budget-friendly materials
• For example, laminate floors will cost less than hardwood, but remember to balance affordability with durability

Get an accurate quote for your building project

There are two ways we can help you to get accurate quotes for your construction project:

• Enter some details to our request a quote form and a selection of approved local contractors will contact you directly with prices
• Alternatively, add your postcode, below, to browse a list of trusted tradespeople in your area

Cost comparisons for common projects

This home construction cost guide can be used in several ways:

• Perhaps you’re looking for the cost per m² for a house renovation in the UK
• Or maybe you’re trying to calculate building costs per m² for an extension
• It could be that you want to be able to understand the cost of building a house

Let’s look at the average build cost in the UK for these common projects.

New build homes

Building a house involves a huge number of different processes, starting with surveying the site and digging the foundations. Your construction crew will need to build the substructure, lay drains, and pour the floor slab.

Other works include building the external walls, installing the roof structure, insulating the property, and adding internal walls. Then there are finishes, such as doors and windows, plus installing all the services and finally, landscaping and decorating.

The cost of building a house is usually calculated in square metres and averages around £1,800 per m².

However, the size and design of your house will influence its cost:

• Average cost to build 2 bedroom house: £226,812
• Average cost to build 3 bedroom house: £286,500
• Average cost to build 4 bedroom house: £358,125

Extensions and renovations

Extending, renovating, or converting part of your property are popular ways of creating the home you want without the cost or stress of moving.

• The average cost of a single-storey house extension (30m²) is £72,000 
• Meanwhile, the average cost of a double-storey extension (60m²) will sit in the region of £130,000 
• Renovating a 3-bedroom house typically averages around £76,690
• The average cost of a loft conversion on a semi-detached or terraced property is £50,000

External structures

Standalone projects such as building a garage, garden office, or even a brick wall often cost less to build per m² due to simpler designs.

• Building a single skin, brick garage (6m x 6m x 2.5m) costs, on average, £28,000
• A mini garden office (delivered for self-assembly) normally costs around £5,250
• A 1m x 4m brick wall costs, on average, £825 for a single skin wall and around £1,200 for a double skin wall

Find and book your trade with us and we'll guarantee their work up to £1,000*.

Guaranteed for 12 months. Eligibility and T&Cs apply

Other build costs to budget for

The average building cost per sq m doesn’t take absolutely everything into account. There are other professional services and jobs you’ll need to factor into your budget.

For example, hiring an architect and/or building engineer, and employing a project manager. Experts recommend allowing an extra 15% of the total build cost to cover these expenses.

You may also want to allow an additional 8% for any permits, permissions, or consents you may need.

Expert tips for managing build costs

• Plan your budget effectively (to ensure affordability and minimise stress)
• Set a realistic contingency of between 10-15% (for unexpected expenses)
• Hire trusted and approved professionals (for quality, efficient work)

Find approved tradespeople and industry professionals near you

Hiring the right team for your build is crucial to ensure you’re charged a fair and competitive price, and that the work is carried out to a high standard, without unnecessary delays, and in line with building regulations.

We check and approve all our members before they’re able to work alongside our trusted tick, passing up to 12 rigorous checks to be listed in our leading directory.

So when you’re ready to get started, simply enter your postcode below to see the tradespeople who come highly rated in your area. We’ve done all the hard work, making it easy for you to find trades you can trust for your project build.

FAQs

What’s the average building cost per square metre in the UK?

In the UK, build costs per m² typically range from £1,775 - £3,000.

How do I calculate the cost of building an extension?

Measure up the floor area you desire in sq m. Then multiply this figure by the average cost of an extension per square metre, which is £2,400. This will give you a ballpark cost for building an extension.

Do VAT rates apply to new builds in the UK?

VAT is zero-rated for new builds, but other projects, such as renovations, may incur VAT at the standard rate.

What does RICS guidance say about UK build costs?

The Royal Institution of Chartered Surveyors (RICS) recommends getting detailed estimates to include all aspects of the build, including indirect costs such as professional fees and insurance.

What factors influence the build cost per m²?

Location, size of project, design complexity, materials, and labour rates are the main factors affecting building costs.

What are the additional costs to consider beyond construction?

Professional fees, such as architects and structural engineers, permits and planning application fees, VAT, and unforeseen expenses can add a significant percentage to your overall build cost.

Do I need to hire a project manager for my build?

You can manage the build project yourself, without a project manager, but it’s important to bear in mind that building can be extremely complicated. Any delays, mixups, or lack of coordination on site can end up costing you more. A project manager has the knowledge and experience to help everything run as smoothly as possible.

How much does planning permission cost?

The cost of submitting a planning application is £578 in England. However, you’ll also need to spend money to have relevant professionals prepare the plans and conduct any necessary surveys. Another potential cost relates to addressing any conditions attached to the consent, if and when it comes through.

Do I need self-build insurance?

Taking out a specialist self-build policy is highly recommended. This typically covers physical damage, liability, and legal expenses. You may also wish to consider taking out a structural warranty to cover your self-build project for up to ten years after completion.