How to Verify a GSTIN — and Why It Protects Your Input Tax Credit

5 min read · GST

A GSTIN carries a surprising amount of information — and checking it before you deal with a vendor is one of the cheapest ways to protect your input tax credit. Here's how to read and verify one.

What the 15 characters mean

A GSTIN is built as State code (2) + PAN (10) + Entity number (1) + "Z" + Checksum (1). So positions 3–12 are literally the PAN of the business, positions 1–2 tell you the state, and the 13th character is the registration serial for that PAN in that state. The last character is a checksum that guards against typos.

Two levels of verification

First, format validation: is it 15 characters, does the state code exist, does the embedded block look like a valid PAN? This catches typos and fabricated numbers instantly and works offline. Second, live status: is the registration currently active (not cancelled), and does the legal name match? That requires a GST-portal lookup.

Validate and decode one now → our free GSTIN validator checks the structure and shows the state, embedded PAN and entity type in a second — no sign-up.

Why it protects your input tax credit

You can only claim input tax credit on purchases from a validly registered, active supplier whose invoices actually reach GSTR-2B. If a vendor's GSTIN is wrong, cancelled, or fabricated, your ITC gets blocked at matching time — and you carry the cost. Verifying up front, at onboarding, is far cheaper than reversing credit later.

Verify every vendor automatically

OnGravy validates vendor GSTINs at onboarding and flags mismatches before they block your input tax credit at GSTR-2B matching.

Try OnGravy →

General information, not tax advice. Always confirm active status on the GST portal before claiming credit.