Verify the format and checksum of any Indian GST Identification Number (GSTIN). Decodes state, PAN, and taxpayer type.
| Position | Characters | Meaning |
|---|---|---|
| 1–2 | 01–37 | State / UT code |
| 3–12 | PAN Number | Taxpayer's PAN (5 letters, 4 digits, 1 letter) |
| 13 | 1–9, A–Z | Entity number (for multiple GST registrations under same PAN) |
| 14 | Z | Always 'Z' (default) |
| 15 | 0–9 or A–Z | Checksum digit (MOD-37 algorithm) |
India's Goods and Services Tax (GST) was introduced on 1 July 2017, replacing a complex web of central and state taxes including VAT, service tax, and central excise duty. Every business with an annual turnover exceeding Rs. 40 lakhs (Rs. 20 lakhs for service providers in most states) is required to register and obtain a 15-character Goods and Services Tax Identification Number (GSTIN). As of 2024, over 1.4 crore businesses are registered under GST, making GSTIN validation an everyday requirement for B2B transactions, invoice verification, and compliance.
A valid GSTIN follows a strict 15-character alphanumeric format: the first two digits represent the state code (01 for Jammu and Kashmir, 33 for Tamil Nadu, 27 for Maharashtra, etc.), characters 3 to 12 correspond to the registrant's PAN number, character 13 is an entity number for multiple registrations under the same PAN, character 14 is always "Z," and character 15 is a checksum digit computed using the Luhn-like algorithm specified by GSTN. This validator checks all these components instantly.
Under Section 16 of the CGST Act 2017, a buyer can claim Input Tax Credit (ITC) only if the supplier's GSTIN is valid and their returns are filed. Invalid or fraudulent GSTINs have been used in GST invoice fraud cases investigated by DGGI (Directorate General of GST Intelligence), resulting in crores of rupees in penalties. Accounts payable teams, procurement officers, CA firms, and e-commerce operators use GSTIN validators routinely to avoid compliance risk and ITC rejection during GSTR-3B reconciliation.