What is a Spanish CIF?

The CIF (Código de Identificación Fiscal) was the tax ID for Spanish companies and entities: a letter for the organisation type, 7 digits and a control character. Since 2008 it has been merged into the NIF for legal entities, but the same structure and check rules still apply.

How is the CIF control character calculated?

Take the 7-digit body, double the digits in odd positions (adding their digit-sum when over 9), add the even-position digits as-is, then the control digit is (10 minus the total modulo 10) modulo 10. Some organisation types use that digit, some use the matching letter from the table JABCDEFGHI.

Is my CIF uploaded anywhere?

No. The check runs entirely in your browser using client-side JavaScript — nothing is uploaded or stored.

Spain CIF Validator — Gera Tools

Spanish CIF validator

Validate a Spanish CIF (company / entity tax ID) by checking its organisation-type letter and final control character. The control character is derived from the 7-digit body and may be either a digit or a letter depending on the organisation type — this tool checks whichever form is valid and tells you what to expect when it does not match.

It runs entirely in your browser, so the number you type is never uploaded. A structurally valid CIF is not guaranteed to be one that has actually been issued — this is a format and control-character validator only.