GSTIN Verification Tool
Free GSTIN verification tool. Check a GST number's format and mod-36 check digit instantly, and decode its state code, embedded PAN and registration number.
About the GSTIN Verification Tool
A GSTIN verification tool checks that a 15-character GST number has the right format and a valid mod-36 check digit, then decodes its state and state code, embedded PAN and registration number. It runs in your browser and does not confirm live registration on the GST portal.
A GSTIN is 15 characters long and self-describing: the first two digits are a state code, the next ten are the taxpayer's PAN, the thirteenth is a registration/entity number, the fourteenth is always "Z", and the fifteenth is a checksum digit computed from the other fourteen using a mod-36 algorithm. This tool decodes all of that and verifies the checksum in one pass, catching a mistyped or fabricated GSTIN before it ends up on an invoice.
This is a format and checksum check, not a live lookup against the GST portal — it can prove a GSTIN is malformed (wrong length, invalid state code, checksum mismatch), but only the government's own GSTN system can confirm that a well-formed GSTIN belongs to a real, currently-registered taxpayer. For that final confirmation, verify on the official GST portal (services.gst.gov.in) before relying on it for input tax credit.
Typing errors are the single most common GSTIN problem — a transposed digit or a misread character — and the checksum catches almost all of them instantly, before a wrong GSTIN gets printed on a real invoice or claimed against ITC. Paired with the Letterhead Compliance Checker, this covers the two places a wrong GSTIN causes the most damage: your own stationery, and a vendor's invoice you're about to accept.
Frequently asked questions
- Does this confirm a GSTIN is actually registered with the government?
- No — it verifies that the format and check digit are mathematically valid, which catches typos and fabricated numbers. Only the official GST portal (services.gst.gov.in) can confirm a GSTIN belongs to an active, real registration.
- What does each part of a GSTIN mean?
- State code (2 digits) + PAN (10 characters) + entity/registration number (1 character, for taxpayers with multiple registrations on the same PAN in a state) + a fixed "Z" + a checksum digit (1 character) computed from the first 14 characters.
- Is my GSTIN sent anywhere when I check it here?
- No — the entire check runs in your browser using a fixed formula. Nothing you type is transmitted or stored.
- Why did a real-looking GSTIN fail the check?
- The most common reason is a single mistyped or transposed character — the checksum is extremely sensitive to that. Re-check the source document carefully; a genuine GSTIN issued by the GST department will always pass this format check.
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