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GST State Code 18: Assam
Every GSTIN registered in Assam starts with 18. Here is what the code means for your invoices, which tax head applies, and how to check a GSTIN.
- GST state code
- 18
- State / UT
- Assam
- Type
- State
- Capital
- Dispur
- Local (intra-State) supply
- CGST + SGST
- Supply to another state
- IGST
How 18 appears in a GSTIN
- Digits 1–2 (18): the state code, which shows the registration is in Assam.
- Characters 3–12: the PAN of the business or proprietor (illustrative PAN shown).
- Character 13: the entity number for registrations under the same PAN in this state (1–9, then A–Z).
- Character 14: "Z" by default.
- Character 15: a check character calculated from the first 14. Verify it with the GSTIN validator.
Check if a GSTIN is from Assam
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Enter a 15-character GSTIN.
Good to know about code 18
Assam is the gateway to the North-East and borders seven states, so most goods moving into the region pass through an Assam-registered supply chain.
CGST, SGST/UTGST or IGST for Assam
Compare the supplier's state code with the place of supply. If both are 18, the supply is intra-State and the rate is split as CGST + SGST. If the place of supply is in any other state or UT, the full rate is charged as IGST.
| Supply from Assam (18) to | Code | Tax |
|---|---|---|
| Assam (same state) | 18 | CGST + SGST |
| Arunachal Pradesh | 12 | IGST |
| Nagaland | 13 | IGST |
| Manipur | 14 | IGST |
| Mizoram | 15 | IGST |
| Tripura | 16 | IGST |
| Meghalaya | 17 | IGST |
| West Bengal | 19 | IGST |
Not sure where the place of supply is? Use the place of supply calculator, or let the GST invoice generator pick the tax head from both GSTINs.
Frequently Asked Questions
Which state has GST state code 18?
18 is the GST state code of Assam. Every GSTIN registered in Assam begins with the digits 18.
What is the GST state code of Assam?
The GST state code of Assam is 18. It is the first two digits of the 15-character GSTIN.
Does a GSTIN starting with 18 mean the business is in Assam?
It means the registration belongs to Assam. A business registers separately in each state it supplies from, so the same company can hold GSTINs with other state codes. The shipping address on an invoice can also differ from the registered state.
Which GST applies on a sale within Assam?
When the supplier is registered in Assam and the place of supply is also Assam, the supply is intra-State, so the rate is split as CGST + SGST. For example, an 18% item is charged as 9% + 9%.
Which GST applies on a sale from Assam to another state?
Supplies from Assam (18) to a place of supply in another state or UT are inter-State and carry IGST. For example, a sale to a buyer in Arunachal Pradesh (12) is charged IGST at the full rate.
Is Assam a state or a Union Territory under GST?
For GST, Assam is classified as: State.
Can one business have more than one GSTIN starting with 18?
Yes. A business can hold several registrations in the same state, for example for separate business verticals. They all start with 18 and share the same PAN in digits 3 to 12, but the 13th character (the entity number) is different.
Is the state code in a GSTIN the same as the place of supply?
No. The state code shows where the supplier or buyer is registered. The place of supply is worked out under the IGST Act rules for goods or services. Comparing the supplier's location with the place of supply decides whether CGST + SGST or IGST applies.
What happens if an invoice uses the wrong tax because of the state code?
If CGST + SGST is charged where IGST was due (or the other way round), the supplier generally has to pay the correct tax and claim a refund of the amount paid under the wrong head. The buyer's input tax credit can also be held up until the invoice is corrected, so check the buyer's GSTIN before invoicing.
Has GST state code 18 ever changed?
No. 18 has been the code for Assam since GST began in July 2017, and the GST 2.0 rate changes did not affect state codes.