Costs & Budgeting
How to budget for a home improvement project
A practical approach to setting a realistic budget before you start getting quotes.
Start with a clear brief of what the space needs to do, check that against published industry cost ranges for your project type, add the statutory and professional fees that sit outside the build price, and build in a contingency. Get more than one quote, and make sure each one covers the same scope before comparing them.
Last updated 20 August 2026
Start with the brief, not the number
A clear, room-by-room brief of what you actually need the space to do makes it far easier to get an accurate quote, and much easier to spot where costs can flex without compromising the parts of the project that matter most to you.
Use published ranges as a starting point
Published UK cost guides - ours included - give a general per-m² or total-cost range for a project type, sourced from named industry bodies rather than invented. Treat these as a sense-check for a budget range, not a quote for your specific property; your own quotes will reflect your actual site, specification and location.
Add what sits outside the build price
Design fees, statutory application fees, a structural engineer, a party wall surveyor where relevant, and contingency all sit outside the headline build cost - see our guide to hidden costs for the full list. Leaving these out is the most common way a budget ends up short.
Compare quotes like for like
A lower quote isn't necessarily a better one if it excludes items another quote includes - fittings allowances, waste removal, or making good after the work. Ask each quote to itemise what's included and what's a provisional sum, so you're comparing the same scope.
FAQs
How much contingency should I budget for?
There's no fixed rule, and it varies with the age and condition of the property - older buildings tend to carry more uncertainty about what's behind the walls. Setting aside a meaningful percentage of the total budget as contingency, rather than assuming the first quote is the final figure, is standard practice.
Take this further
Have a question about your own project?
Related guides
More on costs & budgeting
Hidden costs to budget for on a building project
The costs that sit outside the headline build price, and catch people out when they're not budgeted for.
Is £30,000 enough for an extension?
What that budget realistically stretches to, and where it goes further.
Why building quotes vary so much for the same project
Why two quotes for what looks like the same job can differ by tens of thousands of pounds.