Verify any 15-digit GST number's format + checksum — offline, instant.
15 characters: 2-digit state code + 10-character PAN + 1-digit entity number + 1 default character (Z) + 1 checksum digit. Example: 27AAPFU0939F1ZV (Maharashtra GSTIN).
This tool checks format + checksum (detects typos and fakes). To verify the GSTIN actually belongs to a registered business, use the official GST portal (services.gst.gov.in) — it requires internet and returns the business name and address.
The 15th character of any GSTIN is a computed checksum. If someone randomly generates a 14-digit GSTIN, the 15th digit won't match. This detects fake/typo GSTINs in real-time without a database lookup.
Common reasons: typo in a digit, wrong state code (must be 01-38), invalid PAN pattern in positions 3-12 (must be 5 letters + 4 digits + 1 letter), or wrong checksum. Double-check against your GST certificate.