Brian Dunning's FileMaker Custom Functions

IsValidBankNumber ( banknummer )

Checks a Dutch banknumber for validity.

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Theo Ros   Theo Ros

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  Sample input:
IsValidBankNumber ( "123456789" )
  Sample output:

  Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

Returns "true" if banknummer passes the '11-proef',
"false" if not or an empty string if banknummer is empty.



Thibaud   Thibaud, Amstelveen, NL
Apr 15, 2012
Bank ING has a serie of bankaccounts that does not follow your algoritm. Those are the former 'Postbank' accounts.
Is there a way to check those too?
Theo Ros   Theo Ros, Hilversum
Apr 15, 2012
for Postbank numbers there is no validity check. The only thing you could do with those is that the numeric value must be less than 100.000.000 (100 million).

Only ING (Postbank) can check if it is a valid, issued number..

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Note: these functions are not guaranteed or supported by Please contact the individual developer with any questions or problems.

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