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GSTIN Validator

Paste any 15-character GSTIN to check its format and checksum, and read the state, PAN and entity details encoded inside it.

Important: This tool checks the format and checksum only. A valid result means the number is mathematically correct — it does not confirm that the business is actually registered or active. For live status, always check the official portal at gst.gov.in.
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What the 15 characters mean

Every GSTIN follows a fixed structure. Here is how it breaks down:

  1. Characters 1–2: the state code (for example, 27 is Maharashtra, 07 is Delhi).
  2. Characters 3–12: the 10-character PAN of the business or person.
  3. Character 13: the entity number for that PAN within the state.
  4. Character 14: the letter Z by default.
  5. Character 15: a checksum character used to detect typing errors.

Why validate a GSTIN before doing business?

A GSTIN appears on every tax invoice you receive, and your input tax credit depends on it being correct. If a supplier's GSTIN on an invoice is mistyped — even by one character — the invoice won't reconcile in your returns and the credit can get stuck. Checking the number takes two seconds and prevents a month-end headache.

Validation also protects you from simple fraud. A surprisingly common trick is quoting a made-up "GST number" on bills to charge tax without being registered. A fabricated number almost never has a valid checksum, so this tool flags it instantly. (A number that passes here could still be someone else's real GSTIN, which is why the final confirmation for a new trading partner should always be the official portal at gst.gov.in, where you can see the registered legal name and status.)

Reading the information inside a GSTIN

A GSTIN is not random — it encodes useful facts you can read at a glance. The first two digits are the state of registration, so a vendor claiming to be in Mumbai should have a GSTIN starting with 27 (Maharashtra), not 07 (Delhi). Characters 3–12 are the business's PAN, which means the 4th character reveals the entity type the PAN was issued to — P for an individual/proprietor, C for a company, F for a firm/LLP, H for a HUF, and so on. The 13th character counts the registrations that PAN holds in that state (1 for the first, 2 for the second…). This tool decodes the state and PAN for you automatically on a valid result.

How the checksum catches typos

The 15th character is computed from the first fourteen using a weighted mod-36 algorithm defined for GSTIN. Change any single character and the expected checksum changes too — which is exactly how this tool detects that "27AAPFU0939F1ZW" is a typo of a number ending in "…ZV". When a check fails, the tool shows you both the entered and the expected checksum so you know whether to hunt for a typo earlier in the string or just fix the last character.

Common situations where this tool helps

  1. Onboarding a new supplier or buyer — validate the GSTIN from their letterhead or quotation before the first invoice is exchanged.
  2. Data entry checks — pasting GSTINs from emails and PDFs introduces stray spaces and look-alike characters (0/O, 1/I); the validator normalises and verifies in one step.
  3. Verifying invoices you receive — a quick check that the supplier's GSTIN on a tax invoice is at least well-formed before it enters your books.
  4. Checking your own documents — before printing your GSTIN on quotations, invoices, signboards or packaging.

Frequently asked questions

Does a valid result mean the GST number is real?
Not necessarily. It means the number is correctly formed and the checksum matches. To confirm a number actually belongs to a registered, active business, use the official GST portal.
Why does my GSTIN show as invalid?
Common reasons are a wrong length, a typo, an incorrect state code, or a mismatched final checksum character. Watch for look-alikes: the digit 0 vs letter O, and 1 vs I.
Can one PAN have multiple GSTINs?
Yes — one registration per state of operation, and optionally separate registrations for distinct business verticals. All of them share the same PAN in positions 3–12; the 13th character distinguishes them.
What does the 4th character of a GSTIN tell me?
It is the PAN entity-type letter: P = individual/proprietor, C = company, F = firm/LLP, H = HUF, A = AOP, T = trust, among others. Useful as a quick sanity check that a "Pvt Ltd" vendor's GSTIN really contains a C.
Is anything I type saved?
No. The check happens entirely inside your browser using the checksum algorithm — nothing is sent anywhere.
Why is the 14th character always Z?
It is reserved by design in the current GSTIN scheme — a fixed letter kept for future use. If the 14th character of a number isn't Z, the number is not a standard GSTIN.