In Cambridgeshire, £2,200–£3,200 per m² of finished floor area for the construction, with £2,600 a reasonable middle figure. That is our own budgeting band, built from Homebuilding & Renovating’s (February 2026) and MyBuilder’s (August 2026) published ranges and adjusted for local costs. A 120m² three-bedroom house is roughly £264,000–£384,000 to build; a 200m² four- or five-bedroom house £440,000–£640,000. A new dwelling is zero-rated for VAT, so there is no 20% to add. Not in those figures: the plot, professional fees (commonly 5–15% of the build cost), site investigation, the £610 planning fee, Building Control, a ten-year structural warranty, utility connections, landscaping and a 10–15% contingency. We itemise every line in the quotation.