These postcodes are structurally valid but fictional, for software testing and form design. This is not a Royal Mail postcode lookup: the Belfast districts are real, the full postcodes are not assigned to any address.
A random Belfast postcode generator combines a real Belfast 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 Belfast postcode district. There are 15 of them, in the BT postcode area, and they all belong to the BELFAST post town in County Antrim. 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.
BT17 6XX — district BT17, sector BT17 6, BELFAST, County AntrimBT6 0XT — district BT6, sector BT6 0, BELFAST, County AntrimBT4 6SR — district BT4, sector BT4 6, BELFAST, County AntrimBT13 1XB — district BT13, sector BT13 1, BELFAST, County AntrimBT11 7UQ — district BT11, sector BT11 7, BELFAST, County AntrimBT14 7RN — district BT14, sector BT14 7, BELFAST, County AntrimThis page produces postcodes on their own. For complete Belfast addresses — building number, street, locality, post town, County Antrim and postcode, laid out to Royal Mail conventions — use the random Belfast 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.
Belfast sits in the BT postcode area. Every district below is a real outward code assigned to the BELFAST post town.
| District | Locality | Structural range |
|---|---|---|
| BT1 | — | BT1 0AA – BT1 9ZZ |
| BT2 | Linen Quarter | BT2 0AA – BT2 9ZZ |
| BT3 | Harbour Estate | BT3 0AA – BT3 9ZZ |
| BT4 | Belmont | BT4 0AA – BT4 9ZZ |
| BT5 | Castlereagh | BT5 0AA – BT5 9ZZ |
| BT6 | Cregagh | BT6 0AA – BT6 9ZZ |
| BT7 | Ormeau | BT7 0AA – BT7 9ZZ |
| BT9 | Malone | BT9 0AA – BT9 9ZZ |
| BT10 | Finaghy | BT10 0AA – BT10 9ZZ |
| BT11 | Andersonstown | BT11 0AA – BT11 9ZZ |
| BT12 | Falls | BT12 0AA – BT12 9ZZ |
| BT13 | Shankill | BT13 0AA – BT13 9ZZ |
| BT14 | Ardoyne | BT14 0AA – BT14 9ZZ |
| BT15 | New Lodge | BT15 0AA – BT15 9ZZ |
| BT17 | Dunmurry | BT17 0AA – BT17 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 Belfast tells you which country's addressing conventions apply, which traditional 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 | BELFAST | Royal Mail post town, written in capitals on the address |
| Postcode area | BT | The leading letters of every district above |
| Traditional county | County Antrim | ONS administrative geography |
| Country | Northern Ireland | One of the four countries of the United Kingdom |
| Region | Northern Ireland | The country name |
| Dialling code | 028 | Ofcom National Telephone Numbering Plan |
Royal Mail has not required a county line on addressed mail since 1996. BELFAST plus a correct postcode is sufficient; County Antrim 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 Belfast address is deliverable, that is a licensed Royal Mail Postcode Address File lookup, and no generator can answer it.
The districts are real: all 15 of them are Royal Mail outward codes genuinely assigned to the BELFAST 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 Belfast in a district lookup and passes validation, but it is not a live delivery point and must never be used to send post.
15, in the BT postcode area: BT1, BT2, BT3, BT4, BT5, BT6, BT7, BT9, BT10, BT11, BT12, BT13, BT14, BT15, BT17. That is the count for the BELFAST 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 "Belfast".
BT. The postcode area is the leading letter or letters of the outward code, so every Belfast postcode begins BT — for example BT1. The digits that follow identify the district within the area.
This page generates postcodes on their own and explains Belfast's district structure. The Belfast 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=belfast&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.