Find Your Eircode in Ireland

Ireland had no national postal code at all until 2015, which is remarkably late and explains a lot about how Eircode was designed. Dublin had numbered postal districts — Dublin 1, Dublin 4, Dublin 6West and the rest — but outside the city there was nothing, and a very large number of rural addresses had no unique street address either. Tens of thousands of houses shared a townland name with their neighbours and no house number at all.

That was the problem Eircode was built to solve, and it explains why it went straight to the finest possible level. Rather than dividing the country into delivery areas, the system assigned a code to every individual address, more than two million of them at launch. A rural house that previously could only be described as a name in a townland now had a seven-character identifier that belonged to it alone.

The routing key handles the sorting. It names the postal area an item is routed to, in the same way the first part of a postal code does anywhere else, and there are a bit over a hundred of them covering the country.

The unique identifier handles identification, and it was deliberately made non-sequential. The designers did not want a code that revealed how close two properties were, partly for privacy and partly so that the system would not break when a new house was built between two existing ones. The price of that decision is that the second half of an Eircode carries no spatial information whatsoever.

One practical consequence is worth stating plainly: Eircode data is licensed rather than open. Unlike the UK, Australia or the United States, where the national postal geography is published under an open licence, access to the full Eircode database is a commercial arrangement. That is why far fewer services can look Eircodes up than you might expect.

Irish forms increasingly treat the Eircode as mandatory, and because it identifies a single property there is no sensible approximation to type instead.

Look it up properly. The official Eircode Finder takes an address and returns the code for it, and that is the only reliable route. If you have ever received post with your Eircode printed on it, that is the same value.

Do not guess, and do not use a neighbour’s. Because the identifier is unique to one building, a near-miss is not slightly wrong — it is a different property, sometimes on a different street. This is the opposite of how a mistyped ZIP code or postcode behaves, where a wrong digit usually still lands you somewhere nearby.

On an international form that insists on a five-digit ZIP code, an Irish address simply does not fit. The honest response is to find another way to complete the purchase rather than invent a value, because the record that results cannot be delivered against.