GSTIN - Goods and Services Tax Identification Number

GSTIN (Goods and Services Tax Identification Number) is the unique 15-character alphanumeric identifier assigned to every business registered under India's Goods and Services Tax regime. It is issued by the GST Network (GSTN) once registration is approved, and it appears on every tax invoice, return, and e-way bill a registered person raises. The GSTIN is PAN-based, so it links a taxpayer's GST identity directly to their Income Tax record, and a separate GSTIN is needed for each state in which a business is registered.

How the 15 characters are structured

• Digits 1-2: the state code as per the Indian Census 2011 list (for example, 07 for Delhi, 27 for Maharashtra).
• Characters 3-12: the 10-character PAN of the taxpayer.
• Character 13: the entity/registration number for that PAN within the state (1-9 then A-Z, allowing multiple registrations).
• Character 14: the letter "Z" by default, reserved for future use.
• Character 15: a checksum character for validation.

Legal basis

Registration is governed by Section 25 of the CGST Act, 2017, read with Rules 8-10 of the CGST Rules; the certificate of registration in Form GST REG-06 carries the GSTIN. Businesses must register once turnover crosses the Section 22 threshold, currently Rs 40 lakh for suppliers of goods and Rs 20 lakh for services (Rs 20 lakh and Rs 10 lakh respectively in special-category states).

Why it matters

A valid GSTIN lets a business collect GST, claim input tax credit, and file returns such as GSTR-1 and GSTR-3B. Buyers routinely verify a supplier's GSTIN on the GST portal before claiming credit, since credit can be denied if the counterparty's registration is invalid or cancelled.