How we calculate the figuresSources, thresholds and accuracy
Immolytics publishes the prices homes actually sold for in England and Wales. Every figure comes from official records, and a figure is only shown when enough sales stand behind it. This page explains where the data comes from and how we turn it into the figures you see.
Where the data comes from
- Sale prices: the Price Paid Data of HM Land Registry, every sale of a home in England and Wales since January 1995. We keep standard sales at market value (category A) of detached, semi-detached and terraced houses and flats.
- Price changes over a year: the UK House Price Index (UK HPI), published by HM Land Registry with the Office for National Statistics, by local authority and by region.
- Postcodes and areas: the National Statistics Postcode Lookup and the Open Geography boundaries of the Office for National Statistics.
- Place names: OS Open Names, from Ordnance Survey.
- Floor areas, for the price per square metre: energy performance certificates, matched to sales by the unique property reference number (UPRN) of HM Land Registry only. We never use the address fields of a certificate.
Which period the figures cover
Median prices cover the last 12 complete months of registered sales, from July 2025 to June 2026. HM Land Registry says the two most recent months are incomplete, because sales take several weeks to be registered, so we leave them out of the medians.
The list of the latest sales does include those recent months. It shows sales registered up to August 2026.
Pages and the price map also use the last 24 months, from July 2024 to June 2026, to count sales and to colour small areas.
Places, local authorities and postcode districts
- A town is a post town: the town in the postal address. It counts every sale with that town in its address, including its villages and suburbs. The post town of Reading, for example, also covers parts of Wokingham and West Berkshire.
- A locality is a village or suburb named in the postal address, such as Tilehurst in Reading. It has its own page when it has enough sales.
- A local authority is the council area. Its figures can differ from those of the town with the same name, because the two do not cover the same ground.
- A postcode district is the first half of a postcode, such as RG1. A postcode sector adds the first digit of the second half, such as RG1 1.
Thresholds
- A median, a price by property type or a price change is shown only when it rests on at least 11 sales. Otherwise the line says that there are too few sales to publish a figure.
- A price per square metre needs at least 20 sales matched to a floor area in the same area.
- A place gets its own page from 11 sales over 24 months, and is offered to search engines from 30 sales over 24 months.
Medians and ranges
The median is the price in the middle: half the homes sold for less, half for more. Unlike an average, a few very expensive sales do not pull it up.
The middle half of sales is the range between the first and third quartiles: a quarter of homes sold for less, a quarter for more.
The estimate
The estimate starts from the median price of the same type of home in the postcode sector over 24 months, brought up to date with the UK HPI of the local authority. A model built on 1.8 million sales then adjusts it with sales in the same postcode and street, the nearest sales of the same type, the tenure, whether the home is a new build and, when we find it, the earlier sale of the same home.
We tested it on the 269,321 sales registered from January to June 2026, estimated only from earlier sales. The typical error (median error) was 9.2%: 10.0% for detached houses, 8.9% for semi-detached houses, 8.7% for terraced houses and 10.0% for flats. When we found an earlier sale of the same home, it was 8.5%; when we did not, 14.2%.
Every result shows the error measured for its own case. When that error is above 30%, we give no range, only the median price of the area.
The price map
The map shows the 35,672 small areas of England and Wales used by the Office for National Statistics (lower layer super output areas). Each one is coloured by the median price of all homes sold there over 24 months. Areas with fewer than 11 sales are hatched and take the price of their local authority. Colour bands are set so that each holds a similar number of areas.
Updates
We reload the data every month, after HM Land Registry publishes its monthly file. Each page shows the month up to which sales are registered.
What we do not do
- We do not invent figures: when a figure lacks sales, it is not shown.
- We do not sell or pass on the addresses of sold homes. They are shown only in the lists of latest sales, as HM Land Registry allows.
- Estate agencies cannot pay to change a figure or a ranking.