GSTIN Validator & Decoder
Check whether a GST number is structurally valid and decode the state, PAN and taxpayer type — instantly, in your browser.
What is a GSTIN and how is it structured?
A GSTIN (Goods and Services Tax Identification Number) is a unique 15-character identifier assigned to every registered taxpayer under GST. It is built from your PAN, so it is the same business identity carried into the GST system, as set out on the official GST portal.
The 15 characters break down as follows:
- Characters 1–2: the state code (for example, 27 is Maharashtra, 07 is Delhi).
- Characters 3–12: the 10-character PAN of the taxpayer.
- Character 13: the entity number — how many registrations the PAN holder has in that state.
- Character 14: the letter Z by default.
- Character 15: a checksum used to detect typing errors.
This tool checks the structure and recomputes the checksum, so it catches mistyped or fake numbers without needing any login.
Frequently asked questions
How many digits is a GSTIN?
A GSTIN is exactly 15 characters: a 2-digit state code, a 10-character PAN, a 1-digit entity number, the letter Z, and a 1-character checksum.
Does this tool confirm the GSTIN is active?
No. It validates the format and checksum offline. To confirm a GSTIN is currently active and see the registered legal name, use the search service on the official GST portal.
How can I tell the state from a GST number?
The first two digits are the state code. This tool maps that code to the state name automatically.
Is the GSTIN I enter sent anywhere?
No. All validation runs locally in your browser. The number you type is never uploaded or stored.
What does the 13th character of a GSTIN mean?
It is the entity (registration) number, showing how many GST registrations a business holds against the same PAN within one state — 1 for the first, then 2-9 and A-Z for additional registrations.
How is the GSTIN check digit calculated?
The 15th character is a checksum derived from the first 14 characters using a weighted modulo-36 calculation over the 0-9 and A-Z character set. This tool recomputes it to catch typos in the number you enter.
If the checksum is valid, does that mean the GSTIN is real?
Not necessarily. A valid checksum only proves the number is correctly structured — it does not confirm the GSTIN was ever issued or that it belongs to an active, registered business. Always verify live status on the official GST portal.