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House Extension Cost Calculator 2024
How much could your home extension cost?
Use our Home Extension Calculator to get a rough idea of how much your single-storey extension could cost – in just seconds.

Submit your details to reveal an estimate of the cost of your home extension. Then one of our friendly team will give you a call to discuss your extension in detail, including design, planning and your budget.
Use our House Extension Cost Calculator UK
- Step 1. Visit our House Extension Cost Calculator webpage.
- Step 2. Adjust sliders to enter the approximate length & width of your extension.
- Step 3. Click ‘Get My Estimate’ button.
- Step 4. Enter your name, email address & telephone number.
- Step 5. Close pop up to reveal your estimate.
*Please note that this estimate does not include full interior specifications. The final figure may also vary depending on the time of the year and costs of materials.
To provide you with a full quote, we’ll need to know:
- What is your property type?
- What type of extension are you planning?
- Is the extension to the rear or side of your home?
- Is this a single-storey extension?
- What type of roof are you planning to add?
House Extension Cost Per m2
Our house extension cost calculator that calculates per square metre (m2) is an invaluable tool for homeowners planning to expand their living space. This calculator simplifies the budgeting process by providing an estimated cost based on the size of the proposed extension.
Typically, an estimate considers various factors such as location, quality of materials and any additional features like plumbing and electrical work. To use our calculator, begin by imputing the dimensions of the extension to square metres.

House Extension Cost Examples
There are many factors influencing the cost of a house extension, including: type of extension, location, quality of materials, architectural & structural complexity, planning & regulatory costs and construction method. Discover the considerations and get house extensions cost examples here.
Instant Extension Cost Calculator
You can use our extension cost calculator to get an initial estimate instantly. By entering the approximate length & width of your extension, followed by your contact details, you can get an initial estimate within 60 seconds!
Extension Price Calculator
Our house extension calculator can provide you with an initial estimate instantly. For a full quote, please contact us 01202 618374 or email at jobs@ex10.com.