Paste a GST number to check that it is well-formed and that its last character matches the official check digit. You also see the state it was issued in, the PAN inside it, and the type of entity. The check runs in your browser.
HisaabKro keeps each party’s GSTIN on its record, prints it on every invoice, and uses the place of supply to decide CGST/SGST or IGST.
Characters 1–2 are the state code (27 is Maharashtra, 07 is Delhi). Characters 3–12 are the holder’s PAN. Character 13 is the registration number for that PAN in that state (1 for the first, 2 for the second, and so on). Character 14 is Z by default. Character 15 is a check digit calculated from the first 14.
The 4th character of the PAN tells you the entity type: P for an individual, C for a company, F for a firm or LLP, H for an HUF, and so on.
A valid format and check digit catch typing mistakes, which is the most common GSTIN error on invoices. They do not prove that the registration is active. To confirm the status and legal name, use “Search Taxpayer” on the GST portal.