GSTIN

Key facts

• GSTIN is 15 characters: 2-digit state code + 10-character PAN + entity number (1–9, then A–Z, for registrations under the same PAN in a state) + Z by default + a check character.
• The last character is a check digit worked out from the first 14 with a modulus-36 formula, so most typing errors are caught.
• Special GSTINs: UIN for embassies and UN bodies, TDS/TCS registration numbers (based on TAN), and non-resident OIDAR registrations.

Common questions

How do I check if a GSTIN is valid?

The format and check digit can be checked instantly with the GSTIN Checker or ID Decoder on the Tools page. To confirm the registration is active, search the GSTIN on the GST portal.

What does the 13th character of a GSTIN mean?

It is the entity number for that PAN in that state: 1 for the first registration, 2 for the second, and so on, then A–Z after 9.