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Free tool · GST · P2P

GSTIN checker and vendor master cleaner

Check one GSTIN or a whole vendor list for format and check-digit errors, and find duplicate and look-alike vendors.

Free · Runs in your browser · No sign-up

For computation and reconciliation assistance only; not a substitute for formal statutory audit or legal tax advice. This tool checks the structure and check digit only. A GSTIN can be correctly formed and still be cancelled or belong to someone else, so confirm active status on the GST portal (Search Taxpayer) before you pay.

Check one GSTIN

Everything runs in your browser. Nothing you type or open is uploaded, saved or sent.

What is checked

  • 15 characters, letters and digits only (spaces and dashes are removed for you).
  • Characters 1 and 2: a valid GST state or territory code.
  • Characters 3 to 12: the PAN pattern, and the PAN's 4th character (C company, F firm or LLP, P individual and so on).
  • Character 13: the registration number for that PAN in the state (1 to 9, then A to Z).
  • Character 14: normally Z.
  • Character 15: the check digit, worked out from the first 14 characters.

Clean a vendor list

How to read the result

  • Invalid: the GSTIN cannot be right. Ask the vendor for the registration certificate.
  • Duplicate: the same GSTIN appears on more than one vendor code. Block the extra codes so that the same invoice cannot be paid twice.
  • Review: the same PAN is registered in another state (normal for multi-state vendors, but check you are using the right registration), or a similar name has a different PAN.

The full vendor onboarding checklist is in the vendor master template (Q).

Last reviewed 25 October 2026. Spotted an error? Tell us and we will correct it.