Check whether a GST number is correctly formatted and its checksum digit adds up — catch a mistyped GSTIN before it lands on an invoice or e-way bill.
Enter the 15-character GST Identification Number exactly as printed on the invoice or registration certificate.
Format · State Code · Checksum
Enter a GSTIN above to check it.
Checked locally — this doesn't confirm the GSTIN is registered or active on the GST portal.
A GSTIN is 15 characters: a 2-digit state code, the 10-character PAN of the business, a 1-digit entity number (for multiple registrations on the same PAN in a state), a fixed "Z", and a final checksum character computed from the first 14 using a mod-36 algorithm.
This tool checks the format and recomputes the checksum locally in your browser — it does not call the government GSTN database, so it can catch typos but can't confirm the GSTIN is actually registered or active. Always verify a new party's GSTIN on the official GST portal before relying on it.
Onboarding a new party?
No more copy-pasting into a checker separately — party GSTINs are checked right on the form.
Get Started Free