Where the numbers come from.
Nobody shows their working on a price. Here are the main sources Reckon reads, what it does with each, what we’ve tested so far, and what it won’t claim.
What it reads
- HM Land Registry Price Paid Data
- What nearby homes really sold for, and when.
- EPC register
- Floor area, so we can compare £ per square foot, and the energy rating.
- UK House Price Index
- How the area has moved since each sale.
- The listing's own history
- Asking-price cuts, relists, time on the market.
- Live and under-offer listings nearby
- Read once, when you ask for a report, from the listing site’s search near the home. Never crawled, never kept.
- Police.uk
- Recorded crime.
- Environment Agency
- Flood risk.
- Department for Education
- Schools.
Contains HM Land Registry data © Crown copyright and database right 2026. OGL v3.0.
When you ask for a report, Reckon reads the listing you gave it and the listing site’s search results for similar homes nearby, once, for that report. Nothing is crawled, and listing pages are not kept. Reckon works with listings from Rightmove, Zoopla and OnTheMarket, and is not affiliated with any of them. If live data is unavailable, the report uses sold evidence only and says so.
From sales to a range
Each kind of evidence narrows the range. Sold prices set the anchor, floor area makes homes comparable, the House Price Index moves old sales forward to today, and the listing's own history shows what the market has already told the seller.
Fair-value range · Most likely · Walk-away price
- Sold prices nearbyHM Land Registry Price Paid Data
- Floor areaEPC register — so £ per square foot is comparable
- Listing historyPrice cuts, relists, time on the market
- What is on the market nowRead when you ask, for that report only
An illustration of how the range tightens as evidence is added. It is not a real property, and it carries no prices for that reason. When the evidence stays thin, the grade stays low and the report says so.
Where it stops
The honest limits
- It is not a survey. Nobody walks through the home.
- It cannot know the seller’s position, or whether anyone else has offered.
- Flats, areas with few recent sales, and homes compared with sales from further away get a lower grade on purpose.
- Nothing here predicts the future.
- It is never mortgage or legal advice. Talk to a broker and a solicitor.
The first one matters most. Reckon reads data about the home. A RICS Home Survey Level 2 costs £400 to £1,000[4] because a person walks through the building. They answer different questions, and you may want both.
How sure, and why
Every report is graded HighMedium, Low or Very Low. The grade is built from four things:
- How much
- How many comparable sales the area actually gives us.
- How recent
- A sale from last month is worth more than one from 2019.
- How close
- Same street beats same postcode beats same town.
- How consistent
- Whether the £ per square foot agrees with itself.
Directly comparable sales — same street, same type, same size — push the grade up. If live data could not be read, the grade is cut hard and the report tells you that is why. A Low grade is not a failure. It is the honest answer in an area with little to go on.
What we’ve tested, and what we haven’t
We test the estimates against real sales, using only the evidence that existed before each sale. On past sales without live listing data, the ranges were too narrow and the old grade was too generous, so we changed how the grade is set. A High grade is now rarer, and lower grades now miss by more, which is what a grade is for. We haven’t yet measured the reports that use live listings, and we won’t print an accuracy figure until we have.
An automated estimate from public and listing data — not a RICS valuation, survey, or financial advice.
Sources
- HomeOwners Alliance, “How much does a house survey cost in 2026?” — a RICS Home Survey Level 2 costs £400 to £1,000, typically £600–£700 for a £250,000–£350,000 home. https://hoa.org.uk/advice/guides-for-homeowners/i-am-buying/how-much-does-a-house-survey-cost/