About Us

Extension Cost Calculator helps UK homeowners get a clearer starting point for the likely cost of an extension, loft conversion or basement project. Instead of beginning with a blank page, you can use the calculator to build a structured estimate based on the type of work you are considering.

We built the site because many people want a realistic sense of budget before they speak to builders, architects or other professionals. Early-stage figures can make it easier to compare options, decide what is affordable and ask better questions when you are ready to move forward.

The calculator works by asking a few practical questions about your project, then turning those answers into an indicative estimate. It is designed to be simple enough for early planning, while still giving you more structure than a rough guess.

The site is for UK homeowners planning extensions, loft conversions, basement work and similar home improvement projects. All estimates should be treated as a planning starting point only, not as a builder’s quote or a substitute for professional advice.