GST State Code 18 — Assam

How to Read a GSTIN Starting With 18

A GSTIN is 15 characters, and the state code is only the first two. Here is what each part of a Assam GSTIN carries:

Position	Value	Meaning
1–2	18	State code — Assam. This is the part that identifies where the registration sits.
3–12	PAN	The 10-character PAN of the business or person registered.
13	1–9, A–Z	How many registrations that PAN holds in Assam. Usually 1.
14	Z	Fixed. Always Z in a valid GSTIN.
15	check digit	A checksum over the first 14 characters. This is what catches a typo.

Two GSTINs beginning 18 therefore belong to two different businesses registered in Assam — the state code alone never identifies a company. To find out who a number belongs to, look up the GSTIN.

Does a Supply From Assam Attract CGST + SGST or IGST?

The state code is what decides this, and getting it wrong is one of the most common invoicing errors.

• Buyer also in Assam (place of supply code 18) — the supply is intra-state. Charge CGST + SGST, split equally.
• Buyer in any other state or UT — the supply is inter-state. Charge IGST at the full rate instead.

Compare the first two digits of your GSTIN with the first two of the buyer's and the answer follows. Our GST calculator works out the split for you, and place of supply explains the cases where the buyer's address is not the deciding factor.

Codes Near 18

Codes are frequently misread by a digit. These are the ones either side:

Code	State / UT	Alpha
15	Mizoram	MZ
16	Tripura	TR
17	Meghalaya	ML
19	West Bengal	WB
20	Jharkhand	JH
21	Odisha	OD

All 38 GST State Codes

Code 18 is one of 38 state and union territory codes. The complete GST state code list has every one, searchable, with free Excel and PDF downloads you can paste straight into your own sheets.