Free GSTIN validator and decoder

It checks more than the length. It verifies all five components of the GSTIN: the 2-digit state code against the official list of 36 states and union territories, the embedded PAN structure (5 letters, 4 digits, 1 letter), the entity-type code in the fourth letter of the PAN, the reserved 14th character (must be Z), and the MOD 36 check digit in the 15th position. A wrong digit anywhere — even a single transposed character — fails the checksum.

Not necessarily. The most common cause is a typo — one transposed or misread character (O vs 0, I vs 1, B vs 8) changes the check digit. Copy the GSTIN directly from an invoice or the GST portal rather than retyping it. If the number was copied correctly and still fails, the GSTIN may have been issued under a different checksum variant or may genuinely be incorrect — verify it on the GST portal (services.gst.gov.in) for a definitive answer.

No. The validator runs entirely in your browser: it transmits nothing you type and stores nothing — no server, no database, no log. Close the tab and the input is gone. This is deliberate, because a GSTIN is a business identifier and there is no reason it should leave your browser for a format check.

No. This tool validates the format, structure and check digit of a GSTIN — it tells you whether the number is correctly formed. It cannot tell you whether the GSTIN is registered, active, suspended or cancelled, because that requires a live query to the GST portal. For registration status, use "Search Taxpayer" on services.gst.gov.in.

For an occasional check — verifying a new supplier or spotting a typo on an invoice — a validator is fine. If you are checking dozens of GSTINs a month and also need to match them against your purchase register and GSTR-2B, that is billing software territory: it keeps the supplier list, auto-matches GSTINs to invoices, and flags mismatches at filing time rather than at data entry.

The 15th character of every GSTIN is a check digit computed from the first 14 characters using a MOD 36 algorithm prescribed by the CBIC. It catches single-character errors and most transpositions. If you change any one of the first 14 characters, the check digit changes. This is how a validator detects a typo without needing to query the GST portal — the number does not add up.