GST resources
Reading a GSTIN.
A GSTIN is 15 characters: state code, PAN, entity number, a default letter and a check character. The first two digits decide how you tax the customer.
The format
| Characters | Meaning |
|---|---|
| 1–2 | State code (29 = Karnataka, 27 = Maharashtra…) |
| 3–12 | PAN of the business |
| 13 | Entity number within the state |
| 14 | Default letter Z |
| 15 | Check character |
Why the state code matters
If the customer's state code matches yours, charge CGST + SGST; otherwise IGST. TripleBill reads the state from the GSTIN you save on the customer.
Verify before you bill
Check a GSTIN on the GST portal's search before extending credit or claiming a B2B invoice.
How TripleBill helps
TripleBill validates GSTIN format on customers and vendors, derives the state code and uses it for the tax split.
This page is general information about GST in India, not tax advice. Rates, thresholds and rules change; confirm with the GST portal or a chartered accountant before acting.
Frequently asked questions
Does TripleBill validate GSTIN format?+
Yes. Customers, vendors and your own business reject malformed GSTINs and derive the state from the first two digits.
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