Build cost calculatorPrime London 2026
Your build cost, in a minute.
Build your number in four questions.
01 The size
How big is the property?
Your existing floor area. It prices a renovation and scales the overlap with any extension.
02 The work
What are you building?
Pick one or more. We price them as one programme, running together on one site.
How much of the footprint?
Existing house
Specialist rooms, priced after a survey
03 The specification
How is it finished?
Three levels of finish. The specification sets the rate. The postcode adjusts it.
04 The location
Where is it?
The specification sets the rate. The postcode adjusts it. Inner and outer London carry different contractor rates.
Is the house detached?
How it works
Enter the floor area to see your number.
- Enter your floor area.
- Pick the work.
- Choose the finish.
- Add your postcode.
Your estimate
Architecture, interior design and other professional fees are not included. Arrange a call with Nick to talk it through.
That is your range. Three details open the breakdown, the programme and your report. See my full estimate
We call you back within the hour, in working hours. Nick visits, and Matt, our quantity surveyor, prices it. Typically within seven days.
The breakdown
The programme
The order of works
Ranges are guide prices, not fixed quotations. Your property is priced properly in a cost plan.
The figures come from our in-house quantity surveyor. See also loft conversion cost, basement cost and side return extensions.
Your full estimateThree details
Your breakdown, programme and report.
Your name, the property and one way to reach you. Then the full estimate opens above, with a written report to download.
Why we ask A figure means more with the house behind it. Nick reads every estimate himself. He needs the address to price the home, and a way to reach you. Your details go nowhere else.
Your full estimate is open above. We have your details, so the studio can follow it up.
Our quantity surveyor’s own figures sit behind it. Pick the type of work and enter the floor area. You get the construction range for that work. VAT is in the figure. Fees and contingency sit outside it, so we show them separately.
Eight real London projectsPriced
Eight jobs, priced, in the 2026 cost guide.
What a whole project includes, and what sits outside it. Free, by email.
Read these with the ranges
A range is the build. A project is more.
A build range prices construction. A whole project carries more than that, and those are real costs.
So we show them on their own line, rather than inside the rate.
Professional fees, statutory costs, party wall, contingency and VAT are separate.
- Professional fees, set per project by our quantity surveyor
- Statutory costs, including building control and planning
- Party wall awards, where a neighbour is affected
- Contingency, because an existing building carries unknowns
Ranges are guide prices, not fixed quotations. Our quantity surveyor sets the fees and the contingency per project. Your property is priced properly in a cost plan.
After the number
A number today. A cost plan next.
Send us the address and the scope. A budget estimate is typically with you within seven days.
We read the scope
Nick reads it himself. You get a free call, and an honest view of the work.
A budget estimate
Our own quantity surveyor prices the brief. It is typically with you within seven days.
A cost plan
Built line by line from the drawings. Provisional sums are named, not buried.
Your estimate is a guide price. We will tell you what needs to happen next.
From the blog236 notes, free to read
Where these numbers come from.
-
6 min read
What a contractor owes an architect at tender
Six things a tender return should give an architect. Bill of quantities, method statements, shop drawing sign off and subcontractor detail.
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2 min read
Full house renovation cost London
Why a London full renovation is quoted as a band. What puts a project at each end. How to use the figure before drawings exist.
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3 min read
Rear extension cost in London, explained
What a London rear extension costs per square foot. What the build rate covers, what moves it, and how it compares with a side return.