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Municipality Merger Mapper

Search an old municipality name or NIS code to see the successor municipality, new NIS code, merger date and current postcodes — then export the result to CSV.

Local: yes. Your input stays on your device and is not sent to an external service for this tool.

The merger table and current postcode reference are bundled with the site.

The 2024–2025 merger wave

On 1 January 2025 a series of Flemish municipalities merged, and in Wallonia Bastogne and Bertogne merged on 2 December 2024. Each merged municipality received a new NIS code (the Statbel municipality identifier used in statistics, address data and many administrative files), even where the name stayed the same. Postcodes did not change. Files keyed on old NIS codes therefore stop joining cleanly with 2025 data.

Sample mappings

Old municipality    Old NIS   New municipality                 New NIS   Effective
Galmaarden          23023     Pajottegem                       23106     2025-01-01
Gooik               23024     Pajottegem                       23106     2025-01-01
Herne               23032     Pajottegem                       23106     2025-01-01
Beveren             46003     Beveren-Kruibeke-Zwijndrecht     46030     2025-01-01
Zwijndrecht         11056     Beveren-Kruibeke-Zwijndrecht     46030     2025-01-01
Kortessem           73040     Hasselt                          71072     2025-01-01
Hasselt             71022     Hasselt                          71072     2025-01-01
Borsbeek            11007     Antwerpen                        11002     2025-01-01
Bertogne            82005     Bastogne                         82039     2024-12-02

Pajottegem postcodes: 1540, 1541, 1570, 1755

Edge cases

  • Same name, new code. Hasselt kept its name but changed from 71022 to 71072 because Kortessem joined. Matching on names alone misses this.
  • Absorption without a new code. Antwerp absorbed Borsbeek and kept NIS 11002; only Borsbeek's code disappears.
  • Province change. Zwijndrecht moved from the province of Antwerp (11056) to East Flanders as part of Beveren-Kruibeke-Zwijndrecht (46030).
  • Postcodes stay. Addresses keep their postcode; one new municipality can therefore have postcodes from several old ones (2070, 9120, 9130 and 9150 for Beveren-Kruibeke-Zwijndrecht).
  • Time series. Statistics before and after the merger date need the mapping to be summed per new municipality.

Who uses it

Data analysts updating municipality keys in dashboards, researchers building time series across the merger date, municipal and provincial staff preparing reports, and developers maintaining address or postcode tables use the mapper to translate old codes once and correctly. It avoids the silent errors that appear when old and new codes are mixed in one report, and the CSV export can be stored next to the data as the mapping that was applied.

Search old names or codes, then export the mapping as CSV. Check postcodes with the postcode lookup, find the services for an address with who is responsible for my address, or validate a Flemish address with the address checker.

Frequently asked questions

Which Belgian municipalities merged in 2025?

A series of Flemish municipalities on 1 January 2025, such as Galmaarden, Gooik and Herne into Pajottegem, and Beveren, Kruibeke and Zwijndrecht into Beveren-Kruibeke-Zwijndrecht. Bastogne and Bertogne merged on 2 December 2024.

Did postcodes change after the mergers?

No. Postcodes stayed the same, so a merged municipality can have postcodes from each former municipality.

Why does Hasselt have a new NIS code?

Because Kortessem joined it. Hasselt kept its name but the merged municipality received the new NIS code 71072.

What is a NIS code?

It is the official Statbel identifier of a municipality, used in statistics and many administrative files. It is not the same as the postcode.

Is my data sent anywhere?

No. The mapping is bundled with the page and runs in your browser.