GSTIN Validator — verify a GST number instantly
A GSTIN (Goods and Services Tax Identification Number) is a 15-character code issued to every registered taxpayer. Before you issue a B2B invoice or claim input tax credit, it pays to confirm that the GSTIN quoted by the other party is at least structurally valid. This validator checks the format, decodes the state, extracts the PAN and entity type, and recomputes the checksum character using the same algorithm GSTN uses — all in your browser, with nothing sent to any server.
Anatomy of a GSTIN
- Characters 1–2: state code (08 = Rajasthan, 27 = Maharashtra, 07 = Delhi, 09 = Uttar Pradesh)
- Characters 3–12: the taxpayer's PAN; the 4th character of the PAN reveals the entity type (P = individual/proprietor, C = company, F = firm, H = HUF, T = trust)
- Character 13: number of registrations of that PAN within the state (1–9, then A–Z)
- Character 14: always "Z" (reserved)
- Character 15: check digit
How the checksum works
Each of the first 14 characters is mapped to a value from 0 to 35 (digits as-is, A = 10 … Z = 35). The values are multiplied alternately by 1 and 2, the base-36 digits of every product are summed, and the check character is (36 − total mod 36) mod 36 converted back to a character. Example: for 27AAPFU0939F1Z? the algorithm yields "V", so 27AAPFU0939F1ZV is a valid GSTIN while 27AAPFU0939F1ZX is not.
What this tool can and cannot tell you
A passing checksum proves the number is well-formed and not a typo, and the embedded PAN tells you whose registration it should be. It does not prove the registration is active or that the trade name matches. For that, use "Search Taxpayer" on gst.gov.in, which returns legal name, status, registration date and return-filing history. Use both: this tool to catch data-entry errors instantly while billing, and the portal for periodic vendor due-diligence.
The tool also tells you whether a supply from that state to Rajasthan would be intra-state (CGST + SGST) or inter-state (IGST), helping you pick the right tax head on invoices.
Frequently Asked Questions
What does an invalid checksum mean?
Almost always a typing error in one character. Re-check the number against the supplier's invoice or registration certificate.
Can two GSTINs share the same PAN?
Yes. A business registered in several states, or with multiple registrations in one state, has one GSTIN per registration, all containing the same PAN with different state codes or 13th characters.
Does a valid GSTIN guarantee I can claim ITC?
No. ITC also requires the supplier to file GSTR-1 so the invoice appears in your GSTR-2B, and the supplier must have paid the tax.
Which state code is Rajasthan?
08. Delhi is 07, Uttar Pradesh 09, Haryana 06, Gujarat 24, Maharashtra 27 and Karnataka 29.
Disclaimer: This tool is for general information and estimation only. Tax rates and rules change — verify with official sources or a professional before acting. Read full disclaimer.