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Missing Postcode

Why can't I find a postcode?

Updated 23 Sep 2020

Royal Mail’s Postcode Address File (PAF) covers over 30 million addresses and 1.8M UK postcodes. It is updated daily by local councils, and thousands of postmen and women.

Occasionally, there may be instances where you are not able to find a specific postcode on PAF. Listed below are the top reasons why you may not be able to find a postcode.

1. Postcode was terminated

Postcodes regularly undergo reorganisation and removal. When a postcode is removed, it is immediately dropped from the Postode Address File. If a postcode is reorganised, a new postcode(s) is immediately created in its place.

Solution

We provide a service in Postcodes.io, which allows you to check for postcodes which have been terminated. This dataset comes from the Office for National Statistics and is updated quarterly.

For instance, if you wish to check the postcode ST6 2AY, append the postcode to https://postcodes.io/terminated_postcodes/ omitting any spaces. In this instance the URL is https://postcodes.io/terminated_postcodes/st62ay.

{
  "status": 200,
  "result": {
    "postcode": "ST6 2AY",
    "year_terminated": 2018,
    "month_terminated": 7,
    "longitude": -2.192723,
    "latitude": 53.042892
  }
}

If the postcode has been terminated, you will see a terminated year and month.

2. Postcode is under construction

Royal Mail adds and amends thousands of addresses everyday. Some of these additions come from new builds which are not yet occupied.

Unoccupied new builds will have a postcode assigned to them. However, they are not included in the Postcode Address File. Instead they will first appear in a separate dataset called Not Yet Built.

Solution

Check the Not Yet Built dataset for the postcode. Find out more from our Not Yet Built guide.

Contact us if you wish to upgrade your API Key.

3. Postcode is new

If a postcode is definitely occupied and not under construction, then the reason you can't find it may be that your data supplier has a stale dataset.

Solution

Ensure you find a vendor that incorporates Royal Mail's daily address updates, so it's as accurate and up-to-date as can be.

4. Your vendor has inaccurate data

“Why can I find my postcode on Google but not on PAF?”

Royal Mail relies on thousands of people to update works in conjunction with local councils to assign, update and deprecate the Postcode Address File. When these reorganisations happen, it's up to non-PAF address data providers to catch up.

While some datasets like Google Maps, have an effective mapping and on-the-ground team to pick up new addresses; they have trouble detecting which postcodes have been deleted. As a result, terminated postcodes tend to linger on in search engines and mapping providers even after they are no longer usable.

If there is a discrepency between PAF and a third party data vendor, in almost all cases, the alternative data vendor has incorrect data.

Solution

Use PAF, as it is updated daily. If you aren't able to find the postcode on one of Royal Mail's datasets like PAF or Not Yet Built then you can be confident it is not in active use.

How Are Postcodes Decided?

Postcodes are formatted in a hierarchical system. They are divided in two halves where the first part includes the outward code and the second part is the inward code. The outward code represents the postcode area and district, while the inward code represents the sector within the district, followed by the street, which is known as the unit.

For more details, read our guide on UK postcode formats.