Instantly verify any GSTIN's format, PAN, state code, and checksum — free, no signup, runs entirely in your browser.
What Is GSTIN Validator?
A GSTIN Validator checks whether a Goods and Services Tax Identification Number is structurally correct before you rely on it for an invoice, a vendor master, or an ITC claim. Accountants use it to reconcile vendor lists. Freelancers use it before billing a client. Small business owners run it when onboarding a new supplier. If you've ever copied a GSTIN off a signboard or an old invoice and wondered if a digit got mistyped, this is the check you run first. And if it's your own turnover that just crossed the line, check whether you need to register at all with our GST Registration Trigger Checker before validating anyone else's number.
Every GSTIN is a fixed 15-character code, and each position carries meaning:
Position 1–2 : State code
Position 3–12 : PAN of the registered person
Position 13 : Entity/registration number for that PAN in that state (1–9, then A–Z)
Position 14 : Fixed default letter "Z"
Position 15 : Checksum character
[VERIFY: the state-code range 01–38 and the specific numeric code assigned to each state/UT are drawn from the Census 2011 codes GSTN uses on its portal — this needs direct confirmation against a live gst.gov.in listing rather than third-party mirrors.]
Registration itself comes from Section 25 of the CGST Act, 2017, and the certificate format (Form GST REG-06) comes from Rule 10 of the CGST Rules, 2017.
The 15th character isn't random. Give each of the first 14 characters a value from 0–35 (digits keep their value, A=10 through Z=35). Multiply alternating characters by 1 and by 2, starting from the right. Reduce each product to a single digit-sum. Add all 14 results together. Subtract the total's remainder (mod 36) from 36, and that number — mapped back to the same 0–35 character set — is your checksum. [VERIFY: this Luhn mod-36 method isn't published inside the CGST Act or Rules text itself; it's a GSTN system-level validation spec, and this write-up follows the version consistently used across independent GSTIN-validation implementations.]
Suresh runs a small trading firm in Maharashtra and gets a GSTIN from a new supplier: 27AABCU9603R1ZN.
This GSTIN passes both structure and checksum. That doesn't confirm the registration is active — for that, Suresh still needs to search it on the GST portal. It does rule out a typo, which is the most common reason vendor GSTINs bounce back during return filing. If this particular supplier turns out to be a freelancer billing Suresh under GST for the first time, the Freelancer Income Tax and GST Calculator shows how the two taxes stack on their side.
[VERIFY: this section states that Andhra Pradesh's bifurcation left two valid GST state codes in circulation — 28 for registrations issued before the split and 37 for registrations issued after — and that Ladakh carries code 38 following its reorganisation as a Union Territory. Both claims are widely repeated across GST reference sites but need direct confirmation against a primary gst.gov.in or CBIC state-code notification before publishing as fact.]
[VERIFY: Rule 10 of the CGST Rules, 2017 shows a 2025 amendment on CBIC's own repository, effective 1 November 2025 (Notification No. 18/2025-CT). The exact wording change — whether it touches certificate authentication, digital signature language, or something else — needs to be pulled from the notification text itself before stating what changed.] The underlying 15-character GSTIN format is unaffected either way.
No. This tool checks the GSTIN's structure and checksum only, which tells you if the number is well-formed. Whether the business is actively registered, suspended, or cancelled is something only the GST portal's live "Search Taxpayer" service can confirm.
Z is a fixed placeholder in every GSTIN under the current format. It's reserved for potential future use by GSTN and doesn't carry any information about the business today.
No, GSTIN is unique per PAN per state. A business with branches in three states holds three different GSTINs, all sharing the same PAN but different state codes and entity numbers.
That usually points to a typo somewhere in the first 14 characters, most often in the PAN section. Go back to the source document and recheck each character before assuming the GSTIN itself is fake.
No. Validation runs entirely in your browser using JavaScript. Nothing gets sent to a server or saved anywhere.
28 was the code used before the state's bifurcation; 37 came into use for registrations issued after. [VERIFY: exact cutover date and whether 28 remains open for any new registrations needs confirmation against a primary CBIC or GSTN source.]
A PAN is only 10 characters. A GSTIN wraps that PAN inside a 15-character structure with a state code, entity number, Z, and checksum. Entering just the PAN will always fail the length check. Run the PAN by itself through our PAN Card Validator first, then come back here to check the full GSTIN once you have it.
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