CLABE
The CLABE (Clave Bancaria Estandarizada, Spanish for "standardized banking cipher" or "standardized bank code") is a banking standard for the numbering of bank accounts in Mexico. This standard is a requirement for the sending and receiving of domestic inter-bank electronic funds transfer since June 1, 2004. The CLABE replaces the old Mexican account numbering scheme where the account number had 11 digits. The provision for CLABE standardization was issued by the Asociación de Bancos de México (ABM) (Mexican Bank Association) in conjunction with the Banco de México (Mexico's Central Bank). It ensures that the inter-bank fund  transfers, payroll deposits, or automatic service charges are made to the correct accounts. Structure. The 18 digits of the CLABE follows this structure: Bank code. In Mexico, banking institutions are identified by a three-digit number assigned by the ABM. The following table is a Bank Catalogue provided by "El Servicio de Administración Tributaria (SAT.gob.mx)", as of December 4, 2014: City code. This three-digit code refers to the city ("Plaza") where the checking account is located is interna. A bank can have several Branches in a city, therefore the number of the Branch is included in the next, eleven  digit section for the checking account number. Account number. The account number in the financial institution, padded on the left with zeroes to a width of 11 digits. Control digit. The control digit is calculated as the modulus 10 of 10 minus the modulus 10 of the sum of the modulus 10 of the product of the first 17 digits by its weight factor. The first 17 digits of the CLABE are, as mentioned above, the Bank Code, the Branch Office Code and the Account Number. The weight factor of a given digit is: A 17 digit weight is always  37137137137137137. The method is: So, as an example: And so, the complete CLABE is: 032180000118359719