GSTIN Validator

Example: 27ABCDE1234F1Z5

• 27 — State code (Maharashtra). Each Indian state and UT has a 2-digit code (01 to 38).
• ABCDE1234F — The PAN of the taxpayer (10 characters, standard PAN format).
• 1 — Entity number for this PAN in this state. The first GST registration for a PAN in a state gets '1', the second '2', etc., up to '9' then 'A'-'Z' for higher counts.
• Z — Default character (almost always 'Z'). Reserved for future use.
• 5 — Checksum digit (0-9 or A-Z), computed from the first 14 characters.

Each of the first 14 characters is converted to a numeric value:

• 0-9 → 0-9
• A-Z → 10-35

Multiply alternating positions by 1 and 2 (pos 1 × 1, pos 2 × 2, pos 3 × 1, ...). For each product greater than 35, add 'product div 36' to 'product mod 36'. Sum the 14 resulting values. The checksum digit value is (36 − (sum mod 36)) mod 36, converted back to a character.

This is a standard modulo-36 self-checking scheme; it catches almost every single-digit typo and most transposition errors.

If someone fabricates a string that satisfies the format and checksum, the validator will mark it valid — but that doesn't mean the business is registered. For real-world verification (especially before paying a vendor or claiming ITC):

1. Look up the GSTIN on the official portal: gst.gov.in → Search Taxpayer → Search by GSTIN/UIN.
2. Confirm the trade name matches the invoice / supplier you're dealing with.
3. Check the registration is Active, not Cancelled or Suspended.

This validator is a fast first-pass check that catches typos and most fabricated GSTINs.

No. All checks run as JavaScript in your browser. There is no API, no logging, and no third-party tracker on this page. You can confirm by opening DevTools → Network tab and watching while you validate — zero requests fire.