International · Mexico
Mexico CLABE validator.
Check an 18-digit CLABE, the standardized bank account number used for transfers in Mexico. Everything runs in your browser.
How it works: each of the first 17 digits is multiplied by the repeating weights 3, 7, 1, each product is reduced mod 10, the results are added, and the check digit is (10 minus the sum mod 10) mod 10. It must equal the 18th digit.
Inputs
Result
Enter a CLABE and press Check.
How the CLABE check digit works
A CLABE (Clave Bancaria Estandarizada) is 18 digits: a 3-digit bank code, a 3-digit branch or plaza code, an 11-digit account number, and 1 check digit. It is the format Mexican banks use for interbank transfers under the Asociación de Bancos de México (ABM) and Banxico standard.
| Step | What happens |
|---|---|
| 1 | Take the first 17 digits and multiply each by the repeating weights 3, 7, 1, 3, 7, 1 … (17 weights, ending in 7) |
| 2 | Reduce every product mod 10 (keep its last digit) |
| 3 | Add the 17 results and take the sum mod 10 |
| 4 | The check digit is (10 minus that value) mod 10 |
Worked example: 03218000011835971 gives the check digit 9, so the full CLABE is 032180000118359719.
Bank names are not looked up
This tool does not map the bank code to a bank name, because we did not source the code list from a Banxico or ABM publication.
Checksum check only, not proof of an account
A passing result means the 18 digits are internally consistent. It does not confirm the CLABE was issued, is active, or belongs to anyone. Only the bank can confirm that.
Sources
Wikipedia, CLABE (English; cites ABM and Banxico) and CLABE (Spanish); both give the same weights and worked example. Reference implementation: center-key/clabe-validator on GitHub, which computes the same check digit.
Checksum only — not a bank lookup
This tool checks the format and check digit entirely in your browser. A checksum-valid result is not proof the CLABE was ever issued or belongs to anyone. Nothing you type is transmitted, stored, or logged.