Address Lookup API / ONS Postcode Directory

ONS Postcode Directory

The Office for National Statistics assigns geographies to postcodes using the ONS Postcode Directory (ONSPD).

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Key features of ONSPD

2.5 million postcodes
The ONSPD contains current and terminated postcodes using information supplied monthly by Royal Mail
Spatial data
Administrative, electoral, health and other area geographies referenced by postcode
Updated quarterly
ONSPD is updated quarterly to ensure you have the most accurate data

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Adding geospatial data to postcodes

ONSPD is a dataset for business and public bodies looking to reference their spatial data by postcode.

As well as routing and delivering mail, Postcodes can provide boundaries for thematical mapping.

ONSPD links all current and terminated UK postcodes to a wide range of administrative, health, and other geographic areas in which each postcode falls using a point-in-polygon methodology. It helps support the production of area-based statistics from postcoded data.

This data can also be displayed on a map using postcode centroids or postcode-based polygons.

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The Gridlink Consortium

The ONSPD is a Gridlink-branded product that pulls together data from members of the Gridlink Consortium (Royal Mail, Ordnance Survey, National Records of Scotland, Land & Property Services (Northern Ireland) and ONS).

These organisations joined up to form the Gridlink Consortium to promote a core set of postcode-related geographical products. These are maintained by the consortium to avoid duplication and inconsistency in postcode-related datasets.

Adding geospatial data to postcodes illustration

ONSPD fields

The ONSPD includes fields such as:

National Health Service (NHS) area codes
Clinical Commissioning Group codes
Administrative area codes from the Office of National Statistics
Census Output areas and wards

For a full list of additional ONSPD data fields supported by Postcoder, please see our developer documentation.

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How ONS Postcode Directory can help your organisation

Accurate service planning
Use additional geospatial fields such as Clinical Commissioning Group codes to accurately plan and deliver services
Data analysis
Mapping statistical data by postcode allows postcode area-based analysis
Provide local area information
Postcode level geodata allows you to turn postcode areas into coordinates, or search postcodes by location
NHS technology
The NHS administrative data provided by ONSPD can assist companies that create technology for the NHS with planning and delivering their services