GST Number Check — Validate Any GSTIN
Type a GSTIN to see whether its format and check digit are right, which state it belongs to, and the PAN inside it — before it goes on an invoice or a vendor master.
The example is a sample GSTIN. Nothing you type leaves this page.
Result
Valid GSTIN format and check digit
- State
- 27 — Maharashtra
- PAN
- AAPFU0939F
- Holder type
- Firm
- Registration no. in the state
- 1
A GSTIN is 15 characters: a 2-digit state code, the holder's 10-character PAN, a registration number, the letter Z and a check digit. The check digit is calculated from the other 14, so a single mistyped character almost always shows up as an invalid number.
This check runs entirely in your browser. It confirms the number is well-formed; whether it is registered and active is confirmed on the GST portal, which this page links to.
The formula
- Structure
State code (2) + PAN (10) + Registration no. (1) + Z (1) + Check digit (1) = 15- Check digit
Base-36 values × 1, 2 alternately; add quotient and remainder of each by 36; check = (36 − sum mod 36) mod 36
How to read a GSTIN
Characters 1–2 are the state code where the business is registered — 24 for Gujarat, 27 for Maharashtra, 29 for Karnataka. Characters 3–12 are the PAN of the business. The 13th character counts registrations under the same PAN in that state: 1 for the first, 2 for the second, then A–Z after 9.
The 14th character is Z for regular taxpayers, and the 15th is the check digit. The PAN's fourth letter tells the kind of holder: C for a company, F for a firm, P for an individual, E for an LLP.
Valid format is not the same as active registration
A GSTIN can be correctly formed and still be cancelled or suspended. Before you claim input tax credit or onboard a vendor, search the number on the GST portal to see its legal name, status and return-filing record.
Checking the format first saves that search for numbers that can actually exist, and catches typing errors before they reach a tax invoice — where a wrong GSTIN means the buyer cannot take credit.
Keeping GSTINs right in your records
Most wrong GSTINs enter through manual typing into the client or vendor master. An ERP that validates the GSTIN when the master is saved, and fills the state from its first two digits, stops the mistake at the source.
Questions people ask.
How do I check if a GST number is valid?
Enter it above: the tool checks the 15-character format, the state code, the PAN inside and the check digit. To confirm the registration is active and see the business name, search the GSTIN on the GST portal.
What does each part of a GSTIN mean?
The first two digits are the state code, the next ten characters are the PAN, the 13th is the registration number under that PAN in the state, the 14th is Z by default and the 15th is a check digit.
Can a GSTIN be checked without the internet?
Its format and check digit can, as this page does in your browser. Whether it is registered, active or cancelled needs the GST portal.
Why does a GSTIN fail the check digit?
Almost always because one character was mistyped — O for 0, I for 1, or two characters swapped. Compare it again with the registration certificate.
Is my GST number sent anywhere when I check it here?
No. The check runs in your browser; nothing you type is sent to a server or stored.
How can I find the state from a GSTIN?
From its first two digits — see the GST state code list for every code.
Other free tools
Doing this for every item, every day?
A calculator is the right tool once. When it is every item in the store, it belongs in the system that already knows the numbers.