Home postnummer Denmark
Denmark Postnummer validator
How the postnummer format works
- Format
- 4 digits
- Example
- 1050
Things to watch for
- Format-only check — does not confirm the postnummer actually exists
- Always exactly 4 digits with no separators
- Conventionally written directly before the city name, e.g. 1050 København K, not after it
^[0-9]{4}$A Danish postnummer is the 4-digit postcode used to route mail, written immediately before the city name — for example 1050 København K. That ordering is the opposite of what many other countries use, and it’s easy to get backwards when converting an address from a format where the postcode comes last. Anyone validating a Danish shipping address, a checkout form, or a spreadsheet of Danish customer records needs the postnummer in the right 4-digit shape before it’s trusted.
Because a postnummer is a bare 4-digit run with no separator, a transposed or dropped digit produces a code that still looks entirely plausible at a glance — nothing about the shape flags the error.
How this validator works
This tool checks that the input is exactly 4 digits with no letters, spaces, or hyphens, entirely in your browser, with nothing sent to a server.
What a pass doesn’t tell you
A postnummer carries no check digit, so matching the 4-digit shape is the most a client-side tool can confirm — not that Post Danmark has assigned it to a real town or delivery area. Confirming that requires Denmark’s own postnummer lookup.
Scope: this page and tool cover format validation only — not address lookup or confirming a postnummer is currently in use.
postnummer FAQ
What does a Danish postnummer look like?
It's 4 plain digits, written directly before the city name rather than after it — for example 1050 København K for a central Copenhagen address. Post Danmark's predecessor introduced the system in 1967.
Does the first digit of a postnummer mean anything?
Broadly, yes. Numbers cluster lowest around Copenhagen and eastern Zealand, then climb as delivery areas move west and north through Funen and into Jutland. It's a coarse geographic sweep across the country, not a precise district code.
Does a correctly formatted postnummer mean it actually exists?
No. This tool only confirms the string is exactly 4 digits — it doesn't check it against Post Danmark's actual assignment list. Confirming a postnummer is real, and seeing which town it names, requires Denmark's own postnummer lookup.