GSTIN Validator
Validate GSTIN format including state code, embedded PAN, and checksum.
Written by Anil Gautam · Updated
What do the 15 characters of a GSTIN stand for?
A GSTIN packs five parts into 15 characters. Take 27AAPFU0939F1ZV, the sample the page opens with. Its first two digits, 27, are the state code, which the tool decodes as Maharashtra. Characters 3 to 12, AAPFU0939F, are the holder's PAN, and the 13th character, 1, is the entity code that numbers the registrations made under one PAN in the same state. Position 14 holds a letter, Z here, and the last character, V, is a check character calculated from the other 14.
The tool knows the state codes from 01 for Jammu and Kashmir to 38 for Ladakh, and it shows the PAN and entity code under the result without decoding the PAN further. Paste those ten characters into the PAN Card Validator to read the holder type from the fourth letter; the F in AAPFU0939F marks a firm.
How is the GSTIN check character calculated?
Each of the first 14 characters is given a value: digits keep their own value and the letters A to Z count as 10 to 35. Values in odd positions are multiplied by 1 and those in even positions by 2. Each product is divided by 36 and its quotient and remainder are added together, so the Z in position 14 becomes 35 times 2, which is 70, then 1 plus 34, which is 35. The tool sums all 14 results, divides by 36 and subtracts the remainder from 36 (a remainder of 0 gives 0), and the answer, read back as a digit or letter, is the check character.
For the sample GSTIN the total is 221. That leaves a remainder of 5 after dividing by 36, and 36 minus 5 is 31, the value of V. Change one character and the expected check character moves: type 0993 in place of 0939 and the tool reports that it expected P but found V, while a state code of 29 in place of 27 makes it expect R.
Which GSTINs does the format check accept?
The 13th position can be a digit from 1 to 9 or a letter. A business with more than nine registrations under one PAN in the same state gets letters there, starting with A for the tenth, and the tool accepts those. State codes are looked up in a table of 01 to 38 plus 97 (Other Territory) and 99 (Centre Jurisdiction); anything else is reported as unrecognized. Lowercase letters are converted to capitals as you type, so case never causes a failure.
Because the first two digits give the state of registration, comparing them on two GSTINs shows at a glance whether a buyer and a seller are registered in the same state.