What is GSTIN? Structure, Format and How to Verify
Your GSTIN is a 15-character code that identifies your business in the GST system. Every digit carries meaning. Understanding the structure helps you verify supplier GSTINs, catch data entry errors, and protect your input tax credit claims.
The Structure of a GSTIN
A GSTIN always has exactly 15 characters. Here is an example: 27ABCDE1234F1Z5
| Segment | Characters | Example | Meaning |
|---|---|---|---|
| State code | 2 | 27 | State where the entity is registered (27 = Maharashtra) |
| PAN | 10 | ABCDE1234F | PAN of the registered entity - individuals, companies, LLPs, etc. |
| Entity number | 1 | 1 | Distinguishes multiple registrations under the same PAN in the same state (1, 2, 3…) |
| Default character | 1 | Z | Currently fixed as the letter Z - reserved for future use |
| Check digit | 1 | 5 | Auto-generated verification character used to detect errors |
State Codes for Key States
| State | Code | State | Code |
|---|---|---|---|
| Maharashtra | 27 | Delhi | 07 |
| Karnataka | 29 | Tamil Nadu | 33 |
| Gujarat | 24 | Rajasthan | 08 |
| Uttar Pradesh | 09 | West Bengal | 19 |
| Telangana | 36 | Andhra Pradesh | 37 |
| Kerala | 32 | Haryana | 06 |
How to Verify a GSTIN
Visit the GST portal
Go to gst.gov.in. On the homepage, click "Search Taxpayer".
Search by GSTIN or UIN
Select "Search by GSTIN/UIN" and enter the 15-character GSTIN you want to verify.
Review the result
The portal shows the legal name, trade name, registration date, status (Active / Cancelled / Suspended), and the state. Confirm the status is "Active" before transacting.
Why GSTIN Status Matters for ITC
When you purchase goods or services from a supplier, you rely on their GSTIN being active to claim ITC. If the supplier’s GSTIN is cancelled or suspended at the time of the transaction, the GST system will reject your ITC claim - even if you paid full GST on the invoice.
Verify before every large purchase
For high-value transactions, verify the supplier’s GSTIN on the GST portal before finalising the purchase order. A cancelled GSTIN means you absorb the GST as a cost rather than recovering it as ITC.
Multiple GSTINs Under One PAN
A single PAN can have multiple GSTINs - one per state, and the entity number (digit 13) differentiates registrations in the same state for the same PAN. For example, a company with factories in Maharashtra and Karnataka will have one GSTIN starting with 27 and another starting with 29.
Each GSTIN is independently compliant - separate returns, separate ITC pools, and separate tax payment obligations. Stock transfers between GSTINs of the same entity are treated as supply and attract GST.
Common GSTIN Errors to Watch For
- Wrong PAN seeding: If the PAN in the GSTIN does not match the PAN on your supplier’s PAN card, the invoice is invalid for ITC purposes.
- State code mismatch: An invoice from a supplier claiming to be in Maharashtra but with a state code of 29 (Karnataka) is a red flag - either a typo or fraud.
- Non-existent entity number: If the entity number digit is higher than the actual number of registrations that PAN has in that state, the GSTIN is fabricated.
- Inactive GSTIN on invoice: Always check that the GSTIN on any invoice you receive is currently active on the portal.
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