Validate an Argentine CUIT
Check the check digit of an Argentine CUIT, in your browser, for free.
Try an example
This checks the check digit only. It does not confirm the CUIT is registered with Argentina's tax authority (AFIP/ARCA).
Where do you need this?
How the CUIT check digit works
A CUIT (Clave Única de Identificación Tributaria) has 11 digits: a 2-digit type code, an 8-digit number that identifies the person or company, and one final check digit.
The check digit is calculated by multiplying the first 10 digits by a fixed set of weights, adding the results, and taking the remainder after dividing by 11. The check digit is normally 11 minus that remainder — except when the remainder is 0, which makes the check digit 0 (not 11), and when the remainder is 1, which would require a check digit of 10; since no single digit can do that, no valid CUIT exists for those first 10 digits at all.
This checker also accepts a plain 7 or 8-digit DNI (national ID number) for Argentina, since some forms ask for either one.
Frequently asked questions
Is CUIT the same as CUIL?
They're built the same way — 11 digits with the same check-digit formula. CUIT is used for tax and business purposes, CUIL for employment and social security. This checker validates the format either one uses.
Does a valid result mean the CUIT is registered with AFIP/ARCA?
No — see the note below the checker. It means the digits pass the check-digit formula. Only Argentina's tax authority can confirm the number is actually assigned.
Why did a correct-looking number fail?
Usually one digit was mistyped. Changing any single digit almost always changes the required check digit, so the whole number is rejected.
Does formatting with dashes matter?
No. Type it with or without dashes (20-12345678-6 or 20123456786) — the checker strips punctuation before checking.
Related article: Cómo pedir el CUIT en el checkout de Shopify (Argentina, sin Plus) (article in Spanish)
Need this on your Shopify store?
Fiscal ID adds this exact validation to your cart, on any Shopify plan — no theme code, no Plus required.