How to write a Belgian address, and how to check it
A Belgian address looks simple until a box number goes missing or a street has two official names. Here are the rules, and the checks worth automating.
The order of the lines
A Belgian address puts the street before the house number, and the postcode before the locality: Rue de la Loi 16 on one line, 1000 Bruxelles on the next.
French habits put the number first (16 rue de la Loi). Both are understood, but a form that stores the street and the number in separate fields avoids the question altogether.
The box number
Apartments and offices in one building share the house number and are told apart by a box number. It follows the house number, introduced by bte in French or bus in Dutch: Rue de la Loi 16 bte 3.
A box is not a floor or a door code. Without it, the mail for a building of twenty boxes has to be sorted by hand, or comes back.
The postcode
A Belgian postcode has four digits, and the first ones tell the area.
A municipality often has several postcodes, one for each former municipality it absorbed, and the name written after the postcode is the postal locality, which is not always the municipality.
| Postcodes | Area |
|---|---|
| 1000-1299 | Brussels-Capital Region |
| 1300-1499 | Walloon Brabant |
| 1500-1999, 3000-3499 | Flemish Brabant |
| 2000-2999 | Antwerp |
| 3500-3999 | Limburg |
| 4000-4999 | Liège |
| 5000-5999 | Namur |
| 6000-6599, 7000-7999 | Hainaut |
| 6600-6999 | Luxembourg |
| 8000-8999 | West Flanders |
| 9000-9999 | East Flanders |
Two languages, sometimes three
In the Brussels-Capital Region every street and municipality has an official French name and an official Dutch name: Rue de la Loi is also Wetstraat. Both are correct, and a search must find either.
Some municipalities along the language border and the German-speaking municipalities in the east also carry official names in a second language. Store the name the customer chose, and compare addresses on the official identifier rather than on the spelling.
The checks worth running
- The postcode exists and matches the locality.
- The street exists in that locality.
- The house number exists on that street.
- The box number exists when the building has boxes.
- The address is current, not retired.
The first two catch typing mistakes. The last three are what makes a parcel arrive.
Key takeaways
- Street, then number, then box; postcode, then locality.
- The box number is part of the address, written after bte or bus.
- Brussels addresses have two official names, and both must be found.
Frequently asked questions
Is it bte or bus?
bte (for boîte) in French, bus in Dutch. Both introduce the same box number, and either is understood.
Does the postcode tell me the municipality?
Not exactly: it tells the postal locality. A municipality often has several postcodes, and the locality after the postcode can be a former municipality that merged into it.
How do I validate a Belgian address automatically?
Compare it with the official BeST reference: street, number, box and postcode. The Addrly validation endpoints do it in one call and say which part differs.