GSTIN checker — validate a GST number
Check any 15-character GSTIN instantly: state code, PAN, format and the official check digit. Free, and nothing you type leaves your browser.
Checking GSTINs one by one? Let BillSheet do the whole pile.
Upload your purchase or sales invoices and BillSheet reads them into an Excel GST purchase register, sales register with GSTR-1 tables and a GSTR-3B working sheet — checking every GSTIN, tax total and line along the way. Client books in TallyPrime? Download ready-to-import Tally vouchers (beta).
How a GSTIN is built
| Characters | Meaning | Example (27AAPFU0939F1ZV) |
|---|---|---|
| 1–2 | State code | 27 — Maharashtra |
| 3–12 | PAN of the business | AAPFU0939F |
| 13 | Registration number under that PAN in the state | 1 |
| 14 | Always Z (by default) | Z |
| 15 | Check digit | V |
Questions
How do I check if a GSTIN is valid?
Enter it in the checker above. A valid GSTIN has 15 characters: a 2-digit state code, the 10-character PAN, an entity number, the letter Z, and a check digit calculated from the first 14 characters. If the check digit doesn't match, the GSTIN has a typo.
What is the GSTIN check digit?
The 15th character of a GSTIN is a checksum worked out from the first 14 characters with the official mod-36 method. Changing any one character makes it fail, which is why it catches most typing and reading mistakes.
Does this tell me if a GSTIN is active?
No. It checks that the number is correctly formed. To see whether a GSTIN is registered and active, and the business name behind it, search it on the official GST portal (services.gst.gov.in).
What do the first two digits of a GSTIN mean?
They are the state code of the registration — for example 27 is Maharashtra, 07 is Delhi and 29 is Karnataka. They decide whether a supply is local (CGST + SGST) or inter-state (IGST).
Can I check all the GSTINs on my invoices at once?
Yes — with BillSheet. Upload your purchase or sales invoices in GST mode, and every supplier and buyer GSTIN is checked automatically (format, check digit, and CGST/SGST vs IGST for the state), alongside the line maths and tax totals.