How the price-per-sqm method works
The most reliable quick valuation takes recently sold properties similar to yours, divides each sale price by its internal floor area to get a price per square metre, averages those, and multiplies by your property's floor area. It is exactly how a surveyor sense-checks a value, and how investors estimate the GDV (Gross Development Value) of a project before committing.
- Use 3-5 genuinely comparable sales - same area, similar type (flat vs terrace vs semi), similar condition.
- Use internal floor area (gross internal area, in sqm) for both the comps and your property.
- For a refurbishment project, use comparables in finished condition - that gives the post-works GDV.
- The tool shows the average and the low-high range so you can see how tight the evidence is.
Where to find the data (free)
Sold prices come from HM Land Registry's Price Paid Data, searchable free by postcode on the gov.uk Search sold property prices service. Floor areas are on the Energy Performance Certificate (EPC) register, also free - search the address to find its total floor area in sqm. Estate agent listings on Rightmove or Zoopla often quote floor area too. Pair a sold price with its EPC floor area and you have a comparable.
Worked example
Four comps: 300,000 / 75 sqm = 4,000; 320,000 / 80 = 4,000; 285,000 / 72 = 3,958; 310,000 / 78 = 3,974.
Average is about 3,983 per sqm.
Your property is 85 sqm: 3,983 x 85 = about 338,600 estimated value (GDV).
Treat the figure as a guide, not a formal valuation. Price per sqm varies with condition, floor level, outside space, parking and exact location, and a mortgage lender's surveyor may value differently.