India · GST identifier check
GSTIN validator.
Paste a 15-character GST identification number to test its structure and check character, and see exactly which part fails.
Check a GSTIN
Result
Enter a GSTIN and press Validate GSTIN.
How a GSTIN is built
A GSTIN has 15 characters: a 2-digit state code, the holder’s 10-character PAN (five letters, four digits, one letter), a 1-character entity number that counts registrations under the same PAN, the letter Z, and a final check character.
The check character is computed over the first 14 characters. Each character is mapped to its position in 0-9 then A-Z (0 to 35), multiplied by 1 or 2 alternately starting with 1, the product is split into quotient and remainder by 36 and both are added, and the check character is the value that brings the running total to a multiple of 36.
Source: the structure follows the GST Network’s published GSTIN format. Worked example: 27AAPFU0939F1ZV has check character V. Checked October 4, 2026.
Frequently asked questions
Does a valid GSTIN mean the business is registered?
No. A passing check means the structure and check character are consistent. Confirm active registration on the official GST portal.
What does the state code mean?
The first two digits identify the state or union territory of registration. This tool checks that the code is in the range used for GST (01 to 38, 97 and 99), not which state it names.
Why is the 14th character always Z?
The 14th character is a fixed letter Z in the GSTIN structure; the final character is the check.
Format check only
Use the official GST portal to confirm that a GSTIN is active and belongs to the business you are dealing with.