Netherlands (+31 / 0031): 9 digits
Locals write 06 12345678. An API wants +31612345678. Paste any Netherlands number below to see it normalised, validated, and identified.
# free & rate-limited · no signup · live results from the same engine as the API
Since the engine is the same one the API runs, a key does not buy you a better answer. It buys volume, bulk jobs and a signed receipt.
How Netherlands numbers are written
- Country calling code
- +31
- Dialled from abroad
- 0031 (011 31 from the US and Canada)
- ISO country code
- NL
- National number length
- 9 digits
- Trunk prefix
- 0 (dropped in E.164)
- Written locally
- 06 12345678
- E.164 format
- +31612345678
What +31 means
+31 is the country calling code for Netherlands. The same code is written 0031 when you dial out from most of Europe, Africa and Asia, and 011 31 from the US and Canada. All three reach the same place: only the exit code in front of it changes. Whichever one you use, the national trunk 0 is dropped once the country code is in front.
Mobile numbers
Mobiles start with 6 (written 06 nationally).
Converting to E.164
Take the number as written locally (06 12345678), drop the leading 0, then prefix +31. The result is +31612345678: no spaces, no dashes, no parentheses. Store that, and format for display only when you show it to a human.
Why not do it with a regex
A pattern that matches Netherlands numbers today breaks the moment a new mobile range is allocated, and it cannot tell you whether the number is actually assigned. The tool above runs the same numbering-plan engine as our phone validation API, so it also reports line type and region rather than just shape.
Netherlands mobile prefixes
- 06
- Every Dutch mobile
A prefix tells you the range a number was issued from, not which network holds it today — numbers move between operators. For the current carrier you need a live lookup, which is what our phone API returns.
Netherlands area codes by city
- Amsterdam
- 020
- Rotterdam
- 010
- The Hague
- 070
- Utrecht
- 030
- Eindhoven
- 040
- Groningen
- 050
Dutch area codes are two or three digits, and the number adjusts
The big cities have short codes — Amsterdam 020, Rotterdam 010 — and smaller places have three-digit codes such as Bruges-style 0492. The national number is always nine digits in total once the trunk 0 is dropped, so the subscriber part shrinks as the area code grows.
Netherlands phone numbers, answered
What is a 06 number in the Netherlands?
06 is the Dutch mobile range — every mobile in the country starts with it. Internationally the 0 is dropped, so 06 12345678 becomes +31612345678.
How many digits is a Dutch phone number?
Nine after the +31, which is ten as written at home with the leading 0. That total is fixed even though the area code length varies.
That is how a Netherlands number is written. Whether a whole list is worth dialling is the free call list cleaner, or check one number on the spam phone checker.