What is GSTIN?

Last updated: 27 June 2026

GSTIN (Goods and Services Tax Identification Number) is a unique 15-digit alphanumeric code assigned by the government to every GST-registered business in India.

When a business crosses the GST registration threshold — ₹40 lakh turnover for goods in normal states, ₹20 lakh for services — it must register on the GSTN portal and receives a GSTIN. This number is quoted on every tax invoice, GST return, and e-way bill.

How is a GSTIN structured?

The 15 characters follow a fixed pattern: the first two digits are the state code (e.g., 27 for Maharashtra, 29 for Karnataka), the next ten are the PAN of the business, the 13th digit is an entity number for multiple registrations in the same state, the 14th is always "Z", and the 15th is a check digit. A business operating in three states gets three different GSTINs — one per state.

When is a GSTIN mandatory?

Registration (and therefore a GSTIN) is compulsory when aggregate annual turnover exceeds ₹40 lakh for goods or ₹20 lakh for services in normal states (₹20 lakh and ₹10 lakh respectively in special-category states). It is also mandatory regardless of turnover for businesses making inter-state taxable supplies, e-commerce operators, and those liable under the reverse charge mechanism.

Practical example

A trader in Delhi with ₹50 lakh in annual sales will have a GSTIN starting with "07" (Delhi's state code), followed by their 10-digit PAN, then "1Z" and a check digit — for example, 07AABCU9603R1ZM.

Fact box. A GSTIN always begins with a two-digit state code and contains the business's PAN as characters 3–12. If those ten characters don't match your PAN, the GSTIN is invalid.

Frequently asked questions

Can I have more than one GSTIN? Yes — a business with branches or operations in multiple states gets a separate GSTIN for each state, all linked to the same PAN.

Is GSTIN the same as GSTN? No. GSTN (Goods and Services Tax Network) is the government-owned technology company that runs the GST portal. GSTIN is the number assigned to your business.

Sources: GSTN — gstn.org.in; CBIC — cbic.gov.in

General information, not professional advice. Verify on the official portal for your case. Reviewed by a Chartered Accountant; last updated 27 June 2026.

Related: GSTR-1 · E-Invoice (IRN) · GST Registration Guide