Understanding UPRN data sources: open identifiers, free directories, and licensed address data
If you've spent any time working with UK address data, you've probably come across the term UPRN. It comes up in conversations about property, planning, utilities, emergency services, and increasingly, about data quality.
But having access to a UPRN doesn't automatically mean you have access to useful address data. The identifier itself is one thing. The data that surrounds it is quite another.
UPRN stands for Unique Property Reference Number. It's a numerical identifier assigned to every addressable location in Great Britain, from a house or flat to a business premises, a piece of land, or a telephone box.
The number was developed by Ordnance Survey and is maintained as part of a broader system of geographic reference data. Each UPRN is permanent and consistent across different datasets and systems, which makes it a useful common thread when organisations need to link records together. A local authority, a utility provider, and a national health service could all hold data on the same property and, if they all reference the same UPRN, they can match those records.
Access to UPRN data comes through different channels, each with different coverage, currency, and conditions of use. Understanding the differences helps you make better decisions about which source is right for your use case.
In 2020, as part of the UK government's open data agenda, Ordnance Survey released the UPRN identifiers themselves as open data. This means anyone can use, share, or build with a UPRN without needing a licence.
The open release covers two datasets: Open UPRN and Open USRN (Unique Street Reference Number). These are simple CSV files containing the reference numbers and basic spatial coordinates for each property.
For organisations that need to reference a property consistently across systems, or want to link their own data to a national standard, this is a straightforward and free starting point.
What you get:
The UPRN identifier
Easting and northing coordinates (grid reference)
No address text or property details
What you don't get:
The property's postal address
Building name or number
Street, town, or postcode
Information about whether the property is residential or commercial
Whether the property is currently active or has been demolished
The Office for National Statistics publishes the ONS UPRN Directory, commonly referred to as ONSUD. It's updated every 6 weeks and available as a free download. The directory links UPRNs to a range of statistical and administrative geographies, including census output areas, local authority districts, parliamentary constituencies, NHS regions, and rural-urban classifications.
If your work involves analysis at a geographic level, such as understanding how many properties fall within a given catchment area, or mapping UPRNs against health or electoral boundaries, ONSUD provides a useful bridge between individual property references and administrative context.
What you get:
UPRN to geography lookups (local authority, parliamentary constituency, NHS region, and more)
Rural-urban classification
Built environment context (grid reference, country code)
Free to download and use
What you don't get:
Full postal address
Property type (residential, commercial, mixed use)
Occupancy status or date information
Near real-time updates
For statistical purposes, the 6 week release cycle is usually adequate. For operational tasks, such as validating an address at the point of entry or ensuring a delivery record is current, this frequency can leave gaps.
ONSUD works well for research, policy analysis, and geography-linked reporting. It's less suited to anything that depends on knowing whether an address exists and is currently in use right now.
OS AddressBase is Ordnance Survey's commercial address product. It comes in several editions, ranging from AddressBase Core through to AddressBase Premium, with the Premium edition offering the most complete data. Unlike the open or free datasets, AddressBase requires a licence, and the cost varies depending on how you intend to use it.
What you get in return is a significantly richer dataset. Every UPRN in AddressBase is linked to a full, structured postal address as well as a range of other attributes about the property. The data is compiled from multiple authoritative sources, including Royal Mail's Postcode Address File (PAF), local authority gazetteers, the Valuation Office Agency (VOA), and Ordnance Survey's own surveying activity.
What you get:
Full structured postal address (building number, building name, street, locality, town, postcode)
Logical status (approved, provisional, historical, alternative)
Classification codes indicating property type (residential, commercial, educational, and many subcategories)
Start date and last update date
X, Y, and latitude/longitude coordinates
Cross-references to the Postcode Address File and other datasets
Regular updates
AddressBase is scheduled to reach end of life in November 2027, with Ordnance Survey recommending migration to the OS NGD (National Geographic Database) Address Theme as its replacement. For organisations evaluating a direct integration today, that transition is worth factoring into any longer-term planning.
That said, accessing AddressBase directly isn't straightforward for most organisations. Licences are tiered by use case and volume, and the costs can be significant, particularly for commercial applications. Beyond the licensing, working with the raw data requires development resource to ingest, process, and keep it current. For many teams, building and maintaining that infrastructure isn't a realistic option alongside everything else they're working on.
That's where address API providers come in. Rather than dealing with the data directly, you get clean, reliable access to the same underlying information through a simple integration.
Our address data is built on three authoritative sources:
Royal Mail's Postcode Address File (PAF), the definitive record of UK postal addresses,
OS AddressBase, the most detailed address dataset in Great Britain,
OSNI Pointer, the official address dataset for Northern Ireland. Together, they give us comprehensive and current UPRN coverage across the UK.
When someone looks up an address through our API or address finder, the result draws from these sources, which means it reflects the most complete and up-to-date version of that address available. We also return UPRNs as part of every address lookup, so the addresses you capture can be tied back to the national standard. This is vital for organisations linking records across systems, or anyone who needs a consistent property reference that will hold up over time.
View all our UK datasets.