What does it mean when a GSTIN is “structurally valid”?

It means the number is well-formed and internally consistent: it is exactly 15 characters, the first two are a real GST state code, characters three to twelve form a valid PAN pattern, and the final check digit correctly matches the first fourteen characters under the official mod-36 algorithm. Structural validity catches typos and many fabricated numbers. It does not, however, confirm that the registration is currently active — that requires the government’s live database, which this tool links you to.

Does this tool tell me if a GST number is active or cancelled?

No, and no offline tool honestly can. A GSTIN can be a perfectly valid string while the underlying registration has been cancelled or suspended. Only the official GST portal holds live status. This tool validates everything that can be checked from the number’s structure alone, then provides a direct link to the portal’s taxpayer search so you can confirm the current status, trade name, and registration dates against the government record.

How can it check a GST number without the internet or an API?

Because a GSTIN is mathematically structured. The last character is a check digit computed from the first fourteen using a fixed algorithm, much like the Luhn digit on a credit card. The tool recomputes that check digit in your browser and compares it; it also verifies the state code and the embedded PAN pattern. All of this is pure arithmetic on the number itself, so it needs no server call — which is also why the number you paste never leaves your device.

What are the parts of a GSTIN?

Fifteen characters in five parts. Characters 1–2 are the state code (for example 27 for Maharashtra, 07 for Delhi, 29 for Karnataka). Characters 3–12 are the holder’s PAN. Character 13 is the entity number — how many registrations that PAN has in that state. Character 14 is the letter Z by default. Character 15 is the checksum. The fourth character of the embedded PAN also encodes the holder type, which is how the tool can tell a company from an individual or a firm.

Is the GSTIN I paste sent anywhere?

No. The validation runs entirely in JavaScript inside your own browser. The GSTIN is never uploaded, logged, or stored on any server. That makes it safe to check the numbers of suppliers, customers, or your own business without exposing them. Closing the tab clears everything; nothing is retained.

A number failed the check digit — is it fake?

Not necessarily. A failed check digit most often means a typo — a single wrong or transposed character will break the checksum. Re-compare the number against its source document carefully, because correcting one character frequently turns a failing number into a valid one. If the number is copied exactly from the source and still fails, then it is genuinely malformed and should not be trusted until verified on the official portal.

GST

GSTIN Validator

Check any GSTIN’s structure instantly — state, embedded PAN, entity type, and the official check digit — in your browser. Free, no signup, nothing uploaded.

By the Samastam teamLast updated 2026-06-15Editorial standards

Enter GSTIN

Try:

Paste a fifteen-character GSTIN above. Its structure is checked instantly, here on your device — the state, the embedded PAN, the entity type, and the official check digit.

A GSTIN is the 15-character Goods and Services Tax Identification Number assigned to every registered taxpayer in India. It is not random: the first two digits are a state code, the next ten are the holder’s PAN, the thirteenth marks how many registrations that PAN holds in the state, the fourteenth is the letter Z, and the fifteenth is a checksum. Because of that structure, a GSTIN’s validity can be checked offline — and this tool does exactly that, decoding and verifying every part in your browser without contacting any server.

Key takeaways

A GSTIN is 15 structured characters: 2-digit state code, 10-character PAN, 1 entity digit, the letter Z, and a final checksum character.
Because the last character is a mathematical check digit derived from the first fourteen, most typos and many fake numbers can be caught offline — no government lookup needed.
This tool decodes the state, extracts the embedded PAN, identifies the entity type from the PAN, and recomputes the check digit to confirm the number is well-formed.
Structural validity is not the same as active status: a well-formed GSTIN can still be cancelled or suspended. For live status you must check the official GST portal, which this tool links to.
Everything runs locally in your browser. The GSTIN you paste is never uploaded or stored, so it is safe to check a supplier’s or customer’s number here.

What this is and why it matters

Every business that deals with GST handles other people’s GSTINs constantly — on supplier invoices you book for input credit, on customer details you put on your own invoices, on purchase orders and e-way bills. A wrong GSTIN is not a harmless typo. If you claim input tax credit against an invoice carrying an invalid or mismatched GSTIN, that credit can be reversed with interest, and repeated mismatches draw scrutiny. Validating the number before you rely on it is the cheapest insurance there is.

The reason offline validation is even possible is that a GSTIN is deterministic. The fifteenth character is computed from the first fourteen using a fixed mod-36 algorithm, the same way a credit card number carries a Luhn check digit. Change any single character by mistake and the recomputed check digit almost certainly will not match, so the error surfaces immediately. On top of that, the first two digits must be a real state code, and characters three to twelve must form a structurally valid PAN. A number can fail on any of these fronts, and each failure points at a different kind of mistake — a mistyped digit, an impossible state, a malformed PAN.

What this tool deliberately does not do is claim a number is “registered” or “genuine.” Structural validity means the number is well-formed and internally consistent; it does not mean the registration is currently active, because a GSTIN can be cancelled or suspended while still being a valid string. Confirming live status requires the government’s own database. So the tool validates everything it honestly can offline, then sends you to the official portal for the one thing only the government can answer.

How to use this tool

Paste the GSTIN. Type or paste the fifteen-character number into the field above. The input automatically uppercases and strips stray spaces, so you can copy it straight from an invoice or email without cleaning it up first. As you type, a small counter tells you how many characters remain until the full fifteen.

Read the instant result. The moment a complete fifteen-character number is present, the tool validates it locally and shows the outcome. If anything is off — wrong length, an invalid state code, a malformed PAN, or a check digit that does not match — it says specifically which test failed, so you know whether to hunt for a typo or question the number itself.

Review the decoded details. For a well-formed GSTIN, the tool breaks the number down: the state of registration from the first two digits, the embedded PAN, the entity type inferred from the PAN’s fourth character (individual, company, firm, HUF, and so on), the entity’s registration number within that state, and confirmation that the check digit is correct. This is useful for a quick sanity check that the number belongs to the kind of entity you expect.

Confirm live status on the portal. Because no offline tool can know whether a registration is currently active, a clear link takes you to the official GST portal’s taxpayer search, where you can confirm the trade name, status, and registration dates against the government record before you act on the number.

Examples and use cases

Vetting a new supplier before booking input credit

A Bengaluru electronics distributor onboards a new vendor whose invoice shows a Karnataka GSTIN beginning 29. Pasting it into the validator confirms the structure, the 29 Karnataka state code, the embedded PAN, and a matching check digit — then the team follows the portal link to confirm the registration is active before claiming any input tax credit. A single mistyped character would have failed the check digit instantly.

Catching a transposed digit on a purchase order

An Ahmedabad manufacturer’s accounts clerk keys a customer GSTIN into the ERP and the system rejects it. Pasting the same number into this tool shows a checksum failure, which points to a typo rather than a fake number. Comparing against the original document reveals two digits were transposed; correcting them produces a valid GSTIN and the order goes through.

Confirming the entity type matches the paperwork

A Hyderabad startup receives an invoice claiming to be from a private limited company. The validator decodes the embedded PAN’s fourth character as “C,” confirming a company — consistent with the paperwork. Had it decoded as “P” (individual) or “F” (firm), that mismatch would be a flag to ask questions before proceeding.

Checking your own GSTIN on a draft invoice template

A Jaipur consultant setting up a new invoicing template pastes her own GSTIN to make sure it was entered correctly in the letterhead. The tool confirms the Rajasthan state code 08, her PAN, and the check digit, giving her confidence that every invoice generated from the template will carry a correctly formed number.

Screening a batch of supplier numbers before a tender

A Coimbatore procurement officer compiling a vendor list for a tender runs each supplier’s GSTIN through the validator one by one. Two numbers fail — one on the state code, one on the check digit — flagging vendors whose paperwork needs correcting before submission. Catching these offline, in seconds each, saves the rejection that an invalid GSTIN would have triggered later in the tender process, and points the officer to the official portal to confirm the survivors are active.

Frequently asked questions

What does it mean when a GSTIN is “structurally valid”?: It means the number is well-formed and internally consistent: it is exactly 15 characters, the first two are a real GST state code, characters three to twelve form a valid PAN pattern, and the final check digit correctly matches the first fourteen characters under the official mod-36 algorithm. Structural validity catches typos and many fabricated numbers. It does not, however, confirm that the registration is currently active — that requires the government’s live database, which this tool links you to.
Does this tool tell me if a GST number is active or cancelled?: No, and no offline tool honestly can. A GSTIN can be a perfectly valid string while the underlying registration has been cancelled or suspended. Only the official GST portal holds live status. This tool validates everything that can be checked from the number’s structure alone, then provides a direct link to the portal’s taxpayer search so you can confirm the current status, trade name, and registration dates against the government record.
How can it check a GST number without the internet or an API?: Because a GSTIN is mathematically structured. The last character is a check digit computed from the first fourteen using a fixed algorithm, much like the Luhn digit on a credit card. The tool recomputes that check digit in your browser and compares it; it also verifies the state code and the embedded PAN pattern. All of this is pure arithmetic on the number itself, so it needs no server call — which is also why the number you paste never leaves your device.
What are the parts of a GSTIN?: Fifteen characters in five parts. Characters 1–2 are the state code (for example 27 for Maharashtra, 07 for Delhi, 29 for Karnataka). Characters 3–12 are the holder’s PAN. Character 13 is the entity number — how many registrations that PAN has in that state. Character 14 is the letter Z by default. Character 15 is the checksum. The fourth character of the embedded PAN also encodes the holder type, which is how the tool can tell a company from an individual or a firm.
Is the GSTIN I paste sent anywhere?: No. The validation runs entirely in JavaScript inside your own browser. The GSTIN is never uploaded, logged, or stored on any server. That makes it safe to check the numbers of suppliers, customers, or your own business without exposing them. Closing the tab clears everything; nothing is retained.
A number failed the check digit — is it fake?: Not necessarily. A failed check digit most often means a typo — a single wrong or transposed character will break the checksum. Re-compare the number against its source document carefully, because correcting one character frequently turns a failing number into a valid one. If the number is copied exactly from the source and still fails, then it is genuinely malformed and should not be trusted until verified on the official portal.