How to check if a GSTIN is valid (format, checksum and state code)

The 15 characters

• Characters 1 to 2: state code, such as 27 for Maharashtra or 29 for Karnataka
• Characters 3 to 12: the holder's PAN
• Character 13: how many registrations the PAN holder has in that state
• Character 14: the letter Z
• Character 15: a check character that catches typing mistakes

Step 1: check the format

Paste the number into the GSTIN Validator. It checks the pattern and the check character, and shows the state and the PAN hidden inside. If the check character does not match, the number was probably typed wrongly.

Step 2: confirm that it is active

A number can have a perfect format and still be cancelled or not exist. Always confirm the status on the official GST portal using the Search Taxpayer option before you pay or claim input tax credit.

Common mistakes

• Mixing up the letter O and the number 0
• Missing the last character
• Copying spaces with the number

Why it matters

Claiming input tax credit on an invoice from a wrong or cancelled GSTIN can lead to denied credit and notices. A quick check is cheap protection.