GSTIN Validator

What this tool does

GSTIN Validator checks an Indian GST Identification Number’s 15th-character checksum using the official base-36 algorithm, identifies the issuing state from its 2-digit prefix, and decodes the embedded 10-character PAN and registration count.

An Indian GSTIN (GST Identification Number) is a 15-character code built from a 2-digit state code, the taxpayer’s 10-character PAN, a registration-count digit, a default "Z", and a final check character computed via a base-36 checksum algorithm.

This validator runs that official checksum against any entered GSTIN, decodes the issuing state from its 2-digit prefix, and extracts the embedded PAN and registration count, giving a full structural breakdown in one place.

How to use GSTIN Validator

1. Enter the GSTIN (15 characters).
2. Review the Check character result.
3. Check the decoded State code and embedded PAN.
4. Note the registration number and 14th-character checks for anything unusual.

Tips for better results

• The 13th character (registration number on that PAN) counts how many GST registrations the same PAN holds within a single state, 1 for the first registration, 2 for a second, and so on.
• The 14th character is conventionally always "Z" by default under current rules; a different value here is flagged as unusual rather than treated as an automatic error.
• A valid checksum confirms the GSTIN is internally self-consistent, not that it’s currently active or registered; checking actual GST registration status requires looking it up on the official GST portal.
• The embedded PAN can be cross-checked independently with the PAN Validator if you want to confirm its own entity-type structure too.

Common use cases

• Verifying a GSTIN was typed or copied correctly before using it on an invoice or filing.
• Validating GSTIN input in a billing or accounting system before accepting it.
• Looking up which Indian state a GSTIN was issued from.
• Cross-checking the PAN embedded within a business’s GSTIN.

Common mistakes to avoid

• Treating a passing checksum as confirmation the GSTIN is currently active and registered; this only confirms the number is internally mathematically consistent, not its live registration status with the GST authorities.
• Assuming the 14th character must always literally be "Z" with no exceptions; while that’s the default under current rules, this tool flags deviations as "unusual" rather than an automatic hard failure, since rules can evolve.
• Confusing the embedded PAN (characters 3-12) with the full GSTIN; they’re related but are two distinct identifiers used for different purposes.