GST number

A GST number — properly a GSTIN — is the 15-character identifier issued to every business registered under GST in India. It is a 2-digit state code, the holder’s 10-character PAN, a 1-character entity code, a fixed Z, and a check digit. It identifies one registration in one state, which is why a business operating in five states holds five of them.

Check a GST number free See the 15 characters

The 15 characters, position by position

Nothing in a GSTIN is random. Taking the sample number 27AAACR5055K1Z7 apart shows what each block encodes:

Position	Sample	Block	What it encodes
1–2	27	State code	The GST state code of the jurisdiction the registration was granted in — 27 is Maharashtra, 07 Delhi, 29 Karnataka, 33 Tamil Nadu.
3–12	AAACR5055K	PAN	The holder’s Income Tax PAN, embedded unchanged. This is why a PAN search can find every GSTIN issued to an entity.
13	1	Entity code	Counts registrations against the same PAN within the same state. The first is 1; a second business vertical registered separately gets 2, and so on through digits then A–Z.
14	Z	Reserved	A fixed letter Z for every regular GSTIN. It carries no information — it is simply reserved for future use.
15	7	Check digit	A checksum computed from the first 14 characters using a Luhn mod-36 algorithm. It catches typos; it does not prove the number was ever issued.

Structure of a GSTIN, using 27AAACR5055K1Z7 as the worked example.

Deeper on each block: GSTIN format explained, including how the checksum is computed; how many digits a GST number has; and the full GST state code list for characters 1–2.

Who must have a GST number

Liability turns on aggregate annual turnover, computed across all your registrations on the same PAN and including exempt supplies and exports — not just taxable sales in one state. The thresholds differ by what you supply and where.

Category	Threshold	Notes
Supply of goods, most states	₹40 lakh	Aggregate annual turnover. A handful of states retained ₹20 lakh for goods.
Supply of services, most states	₹20 lakh	Applies to service providers across most of the country.
Special category states, goods	₹20 lakh	North-eastern and Himalayan states; a few opted up to ₹40 lakh.
Special category states, services	₹10 lakh	The lowest threshold in the regime.
Inter-state suppliers, e-commerce operators, casual and non-resident taxable persons, ISDs, agents, persons liable under reverse charge	No threshold	Registration is compulsory from the first rupee, whatever the turnover.

Registration thresholds for FY 2026-27. State-level variations exist; confirm against your own state notification.

How the turnover figure itself is built up: annual aggregate turnover under GST. Businesses under the lower turnover ceiling may instead opt into the composition scheme.

How to get a GST number

Registration is entirely online at gst.gov.in and free of any government fee. The application is Form GST REG-01, split into two parts:

1

Confirm you are liable to register

Check your aggregate annual turnover against the threshold for your state and supply type, and check whether you fall into a category that must register regardless of turnover.
2

Complete Part A of Form GST REG-01

On gst.gov.in, submit your PAN, mobile number and email. After OTP verification you receive a Temporary Reference Number (TRN).
3

Complete Part B with the TRN

Fill in business details, promoters and partners, the authorised signatory, the principal place of business and any additional places, bank details and HSN/SAC codes for what you supply.
4

Upload documents and authenticate

Attach proof of business constitution, address proof for each place of business, and photographs. Complete Aadhaar authentication for the authorised signatory where applicable — skipping it routes the application to physical verification.
5

Track the ARN and receive the GSTIN

Submission generates an Application Reference Number you can track on the portal. Once approved, the 15-character GSTIN and the registration certificate in Form GST REG-06 are issued.

Document checklists, common rejection reasons and the timelines in detail: the GST registration process online.

Valid, active, cancelled, suspended

These four words get used interchangeably and mean different things. Valid is a statement about the string; the other three are statements about the registration.

Active

The registration exists and is currently in force. This is the only status that should let an invoice through unchallenged — though an Active GSTIN that has stopped filing returns is still a risk to your input tax credit.

Suspended

Registration is temporarily halted, usually while a cancellation proceeding or compliance review runs. The taxpayer cannot make taxable supplies or issue tax invoices during suspension. It can be revoked and the GSTIN restored.

Cancelled

The registration has been cancelled, either voluntarily or by the department. Invoices dated after the effective cancellation date are not valid tax invoices, and credit claimed against them is exposed.

Provisional / Inactive

Legacy or in-progress states seen occasionally on older registrations. Treat either as "not confirmed" and ask the counterparty before relying on it.

GST number vs PAN vs TAN vs CIN

Four identifiers, four different registers, and one recurring cause of rejected invoices and failed onboarding checks — collecting the wrong one.

Identifier	Length	Issued by	What it identifies
GST number (GSTIN)	15 characters	GSTN / GST department	Identifies one GST registration, state-wise. One entity can hold many.
PAN	10 characters	Income Tax Department	Identifies the legal entity for income tax. Exactly one per entity, and it sits inside every GSTIN issued to it.
TAN	10 characters	Income Tax Department	Identifies a deductor for TDS/TCS purposes. Unrelated to GST and never interchangeable with a GSTIN.
CIN	21 characters	MCA / Registrar of Companies	Identifies an incorporated company. Only companies and LLC-style entities have one — proprietorships and partnerships do not.

Indian business identifiers compared.

The GSTIN–PAN relationship in full: GST number vs PAN. To go from a PAN you already hold to the GSTINs issued against it, see searching a GST number by PAN.

GST number — common questions

A GST number, formally a GSTIN (Goods and Services Tax Identification Number), is the 15-character identifier issued to every business registered under GST in India. It is built from a 2-digit state code, the holder’s 10-character PAN, a 1-character entity code, a fixed Z, and a check digit. It identifies one registration in one state — not the business as a whole.

Fifteen characters, not fifteen digits — the middle ten are a PAN, which contains letters. Any string that is not exactly 15 characters in the state-code + PAN + entity-code + Z + check-digit layout cannot be a real GSTIN.

Businesses whose aggregate annual turnover crosses ₹40 lakh for goods or ₹20 lakh for services in most states (₹20 lakh and ₹10 lakh respectively in special category states). Some categories must register regardless of turnover, including inter-state suppliers of goods, e-commerce operators, casual and non-resident taxable persons, input service distributors and persons liable to pay tax under reverse charge.

Yes, and it is normal. GST registration is state-wise, so an entity operating in five states holds five GSTINs — all carrying the same PAN in positions 3–12. Within a single state, an entity may also register separate business verticals, distinguished by the 13th character.

Valid means well-formed: 15 characters, correct layout, and a check digit that matches. Active means the registration actually exists in the government register and is currently in force. Because the checksum algorithm is public, a fabricated number can be valid and still be entirely fictitious — only a live lookup distinguishes the two.

Search it against government records — on the GST portal’s Search Taxpayer page, or with our free GST number search, which needs no account. Read the status first, then match the legal name, trade name and registered address against the invoice in front of you.

Where Aadhaar authentication succeeds and the application is not flagged for scrutiny, registration is generally granted within about seven working days of submitting Form GST REG-01. Applications requiring physical verification of the premises, or that draw a query, take materially longer.

No. A PAN is a 10-character income tax identifier, one per legal entity. A GSTIN is a 15-character GST registration identifier, one per state registration — and it contains the PAN inside it. You cannot use one where the other is required.

Look up any GST number

Check a GSTIN against live government records — registered name, current status, places of business and GST return filing history. Free, no account.

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