GSTIN (GST Identification Number)
The unique 15-character registration number assigned to every GST-registered entity, built from the state code and the business's PAN rather than issued at random.
In short
- 15 characters, structured rather than random.
- First two digits are the state code; the next ten are the entity's PAN.
- A business registered in several states holds a separate GSTIN for each, all sharing one PAN.
- Must appear on every tax invoice, GST return, and e-way bill.
- Buyers verify a supplier's GSTIN before claiming input tax credit, since a cancelled one can block the claim.
GSTIN is the registration number allotted to every entity registered under GST in India. Unlike a randomly issued reference, it is composed from information: the first two digits are the state code of the state the registration belongs to, the next ten characters are the entity's PAN, the thirteenth reflects the number of registrations the same PAN holds within that state, the fourteenth is a fixed letter, and the last is a check character. Anyone who knows the structure can read a GSTIN and tell which state it belongs to and which PAN sits behind it.
The state-linked structure has a practical consequence that surprises businesses expanding for the first time. GST registration is state-wise, not national, so a business operating in four states holds four separate GSTINs built on the same PAN, files returns separately for each, and maintains separate input tax credit ledgers for each. There is no single national GST number.
GSTIN must appear on every tax invoice the business issues, on each GST return it files, and on every e-way bill generated for the movement of goods. It is the identifier that ties a supply reported by a seller to the credit claimed by a buyer, which is why the number matters well beyond the business that holds it.
That linkage is why buyers routinely verify a supplier's GSTIN before dealing with them, using the search facility on the GST portal. A GSTIN that has been cancelled or suspended, or one quoted incorrectly on an invoice, can prevent the buyer from claiming input tax credit on that purchase even though the buyer did nothing wrong. Verification is a small step that protects the buyer's own credit.
Registration is compulsory once turnover crosses the prescribed threshold, and the threshold differs for goods and services and for special category states. Certain categories are required to register regardless of turnover, including businesses making inter-state taxable supplies, those liable under reverse charge, casual taxable persons, and e-commerce operators. Voluntary registration below the threshold is also permitted, and is common where a business's customers want to claim credit on its invoices.
Also referred to as: GST number, GST registration number, GST identification number.
Frequently asked questions
How many digits is a GSTIN?
Fifteen characters. The first two are the state code, the next ten are the entity's PAN, and the remaining three cover the registration count within that state, a fixed letter, and a check character.
Can one business have more than one GSTIN?
Yes, and it usually must. GST registration is state-wise, so a business operating in multiple states holds a separate GSTIN for each state, all built on the same PAN, with separate returns and separate credit ledgers.
How do I verify a supplier's GSTIN?
Use the search taxpayer facility on the GST portal. It is worth doing before you deal with a new supplier, because a cancelled or incorrectly quoted GSTIN can block your own input tax credit on that purchase.
Is GSTIN the same as PAN?
No, but PAN sits inside it. Characters three to twelve of a GSTIN are the entity's PAN, which is how the tax system links a business's GST registrations to its income tax identity.
Can I get a GSTIN voluntarily if my turnover is below the threshold?
Yes. Voluntary registration is permitted and is fairly common, usually because customers want to claim input tax credit on the invoices they receive, which requires the supplier to be registered.
Disclaimer
This glossary entry is for general informational purposes only and does not constitute professional tax, legal, or financial advice. Rules and rates change, so consult a qualified Chartered Accountant for advice specific to your situation.