Office for National Statistics
Postcode Lookups & Boundaries (ONS)
The free lookup that turns a postcode into everything else — the neighbourhood, ward, local authority, constituency and region it sits in, plus map coordinates. This is the dataset that makes every other dataset here joinable to your own.
At a glance
- Publisher
- Office for National Statistics
- Licence
- Open Government Licence v3 — Contains OS and Royal Mail data © Crown copyright and database right. The standard ONS attribution must be reproduced — check the notes shipped with each release. · what this means
- Updates
- Updated quarterly
- Cost
- Free — open data
- Last checked
- 2026-07-16
RetailPropertyLogisticsProfessional & B2B servicesFinancial servicesGeography & boundaries
What your business can use it for
- Territory planningRoll your customer or sales data up from postcodes to real areas — wards, councils, regions — so you can compare patches like for like and size them against official statistics.
- Market analysisThis is the bridge to almost everything else in this catalogue: government data is published by small area, your data is by postcode, and this is what connects the two.
- Site selectionPlace your sites and your candidate locations into the same official geography that population, deprivation and business data use, so the comparison is honest.
Works with data you already have
- Any postcodes at all — customers, sites, staff, deliveriesPostcodesOne row per postcode unit, carrying OA, LSOA, MSOA, ward, LAD, constituency and region codes plus a coordinate
- You want to put your postcodes on a mapMap coordinatesEach postcode carries a centroid — as OSGB eastings/northings and as WGS84 latitude/longitude
How to get it
- ONS postcode products — start herePortalExplains the difference between the two main products: the National Statistics Postcode Lookup (NSPL) and the fuller ONS Postcode Directory (ONSPD). Released every February, May, August and November.
- Open Geography Portal — download the lookups and boundariesBulk downloadNo account needed. The postcode lookups come as CSV; administrative boundaries are here too, as shapefiles or GeoJSON, if you want to draw the areas on a map.
- postcodes.io — look postcodes up one at a timeAPIA free, no-key API built on the same ONS data by mySociety. Far easier than the bulk file if you only need to resolve a few postcodes, or want to do it live in an application.
What's involved in using it
- This is really a toolbox of many lookup files and map boundaries rather than one dataset, and several versions of the same lookup (older versus newer area definitions) sit alongside each other — so the first task is picking the right file for the job.
- It's the bridge that makes the other datasets usable — it turns a postcode into the neighbourhood, council and region codes everything else is published by — so it's a required extra step, not an optional one.
- Postcodes are retired and created constantly, and old ones stay in the file marked with an end date, so it must be refreshed each quarter and that end-date respected, or you'll silently drop or misplace older records.
The technical detail, for whoever sets it up (4)
- Postcodes are not areas. They are Royal Mail delivery routes that get created, merged and retired.
- A postcode's coordinate is a single point, not a shape — fine for mapping, wrong for measuring how much of an area falls inside a radius.
- The two products differ: NSPL is the one to use if you are allocating your own statistics to areas; ONSPD carries more fields. Pick one and stay with it.
- Attribution is not optional here — the OS and Royal Mail notices ride along with the ONS licence.
Ask us about Postcode Lookups & Boundaries (ONS)
Ask a factual question about Postcode Lookups & Boundaries (ONS) — what it covers, how often it changes, whether it matches the records you keep — and we will answer, free. Or tell us what you are trying to work out, and we will tell you what it would take to get this data working next to the numbers you already have.