A Norwegian postnummer is the 4-digit postal code that routes mail and parcels across Norway. Codes are assigned from 0001 to 9991, and because they increase geographically — starting in Oslo and spiralling outward to the far north — the leading digits are a reliable signal of region. This free tool validates the format and maps the code to its area in your browser.
How it works
- Strip whitespace; the input must be exactly four digits.
- Reject
0000, which is not an assigned postnummer. - Match the numeric value against the assigned range table (
0001–9991) to find the broad geographic area or fylke:0xxx→ Oslo,1xxx–2xxx→ Akershus, Østfold, Innlandet,5xxx–6xxx→ Vestland and Møre og Romsdal,8xxx–9xxx→ Nordland, Troms and Finnmark.
Example
Validate 0150 (central Oslo): four digits, 0xxx → Oslo. Validate 9008 (Tromsø): the 9xxx range maps to Troms. Validate 5003 (Bergen): the 5xxx range maps to Vestland.
Notes
The region mapping is a heuristic based on leading-digit ranges, so it returns the fylke or major area rather than the exact post office. Norway has roughly 5,000 active codes, and a valid four-digit format does not guarantee the specific code is assigned. Confirm against Posten’s official register when delivery accuracy matters. Everything runs locally in your browser.