These postcodes are structurally valid but fictional, for software testing and form design. This is not a Royal Mail postcode lookup: the Cardiff districts are real, the full postcodes are not assigned to any address.
A random Cardiff postcode generator combines a real Cardiff postcode district with a generated inward code, producing a structurally valid postcode that is not assigned to any delivery point.
Every postcode on this page starts from a genuine Cardiff postcode district. There are 7 of them, in the CF postcode area, and they all belong to the CARDIFF post town in South Glamorgan. The three characters after the space are generated to the Royal Mail format rules, so a result validates in any form or database while belonging to no real property.
CF24 6GE — district CF24, sector CF24 6, CARDIFF, South GlamorganCF23 2PD — district CF23, sector CF23 2, CARDIFF, South GlamorganCF14 0XR — district CF14, sector CF14 0, CARDIFF, South GlamorganCF14 1PD — district CF14, sector CF14 1, CARDIFF, South GlamorganCF11 8LT — district CF11, sector CF11 8, CARDIFF, South GlamorganCF23 4TT — district CF23, sector CF23 4, CARDIFF, South GlamorganThis page produces postcodes on their own. For complete Cardiff addresses — building number, street, locality, post town, South Glamorgan and postcode, laid out to Royal Mail conventions — use the random Cardiff address generator.
A UK postcode splits into an outward code and an inward code. The outward code identifies the district; the inward code narrows it to a small group of properties. This generator keeps the first half real and generates the second, which is what makes the output safe to use and still valid.
Cardiff sits in the CF postcode area. Every district below is a real outward code assigned to the CARDIFF post town.
| District | Locality | Structural range |
|---|---|---|
| CF3 | Rumney | CF3 0AA – CF3 9ZZ |
| CF5 | Canton | CF5 0AA – CF5 9ZZ |
| CF10 | — | CF10 0AA – CF10 9ZZ |
| CF11 | Riverside | CF11 0AA – CF11 9ZZ |
| CF14 | Llanishen | CF14 0AA – CF14 9ZZ |
| CF23 | Cyncoed | CF23 0AA – CF23 9ZZ |
| CF24 | Roath | CF24 0AA – CF24 9ZZ |
The structural range is what the postcode grammar permits for each district, not a list of codes Royal Mail has issued. Which sectors and units are actually allocated is Postcode Address File data, which is licensed and not held here — so a generated postcode inside the range may well be unallocated. For test data that is the point.
A postcode carries more than a location. Reading one from Cardiff tells you which country's addressing conventions apply, which preserved county the address sits in, and — if you need a matching telephone number — which dialling code area it falls in.
| Field | Value | Where it comes from |
|---|---|---|
| Post town | CARDIFF | Royal Mail post town, written in capitals on the address |
| Postcode area | CF | The leading letters of every district above |
| Preserved county | South Glamorgan | ONS administrative geography |
| Country | Wales | One of the four countries of the United Kingdom |
| Region | Wales | The country name |
| Dialling code | 029 | Ofcom National Telephone Numbering Plan |
Royal Mail has not required a county line on addressed mail since 1996. CARDIFF plus a correct postcode is sufficient; South Glamorgan is included because plenty of address forms and legacy databases still expect a county.
What they are not for: sending post, verifying an identity, or implying that a property exists. If you need to know whether a Cardiff address is deliverable, that is a licensed Royal Mail Postcode Address File lookup, and no generator can answer it.
The districts are real: all 7 of them are Royal Mail outward codes genuinely assigned to the CARDIFF post town. The three characters after the space are generated, so the full postcode is almost certainly not allocated to any property. That combination is deliberate — the result resolves to Cardiff in a district lookup and passes validation, but it is not a live delivery point and must never be used to send post.
7, in the CF postcode area: CF3, CF5, CF10, CF11, CF14, CF23, CF24. That is the count for the CARDIFF post town as recorded in this site's registry; a post town does not follow council boundaries, so it may not match what a resident would call "Cardiff".
CF. The postcode area is the leading letter or letters of the outward code, so every Cardiff postcode begins CF — for example CF3. The digits that follow identify the district within the area.
This page generates postcodes on their own and explains Cardiff's district structure. The Cardiff address generator produces complete postal addresses — building number, street, locality, post town, county and postcode — laid out to Royal Mail conventions. Use this page when you need postcodes to test a postcode field; use the address generator when you need whole addresses.
Yes, with no API key. Call GET /api/v1/postcodes/random?location=cardiff&count=25 for JSON. Add &seed=1 to get the same set back on every request, which keeps snapshot tests stable. The response carries the outward code, inward code, area, district and sector for each postcode alongside the post town and county.
Structural validation, yes: the format, the length and the excluded letters are all respected, so a correctly written regex or a library check will accept them. A validator backed by licensed Postcode Address File data will reject most of them, correctly, because the full postcode is not an allocated delivery point. If your test suite needs addresses that pass a PAF lookup, no generator can supply them.
Postcodes are generated on demand and never stored. They are for software testing and development only, and must not be used to send post, to imply a real address, or for identity verification.