Free estimator
Full project cost calculator
Estimate drawings + build cost in seconds. Borough-specific. Saved in your URL — share with anyone.
Estimate drawings + build cost in seconds. Borough-specific. Saved in your URL — share with anyone.
This tool estimates the total cost of a project including build, statutory fees and professional fees. As a London market range, expect build cost plus roughly £2,000–£5,000 of statutory and professional fees on a typical London extension or loft. That is a budgeting range, not a quotation.
Statutory fees go to the council and are set nationally for England: a householder planning application is £548 determined in 8 weeks, larger home extension prior approval is £249 over 6 weeks, and a Lawful Development Certificate is £274. Building control is separate again at typically £500 to £1,200 in London.
As a budget envelope before design, not as a target after it. Build cost should drive the design rather than follow it: a scheme drawn without a budget is a scheme that gets value-engineered after planning consent, which usually means a second application. Fix the range first, design to it, then price the defined drawing package with two or three contractors.
Ranges are indicative London market rates observed across domestic projects and are not a quotation. Statutory figures are the England rates in force in 2026 under the Town and Country Planning (Fees for Applications) (England) Regulations. Building control charges are set by each local authority or registered building control approver.
Pick a slot that suits you. No obligation and no sales pressure, just straight answers on your planning route.
