A GSTIN is 2 digits of state code + the 10-character PAN + 1 character for the registration number under that PAN in that state + the letter Z + 1 check digit. In 27AAPFU0939F1ZV, 27 is Maharashtra, AAPFU0939F is the PAN, F (the 4th PAN character) means a firm, 1 is the first registration, Z is the default and V is the check digit.
Part by part
State code (characters 1-2)
The code of the state or Union Territory where the registration is. Common ones: 06 Haryana, 07 Delhi, 08 Rajasthan, 09 Uttar Pradesh, 19 West Bengal, 23 Madhya Pradesh, 24 Gujarat, 27 Maharashtra, 29 Karnataka, 32 Kerala, 33 Tamil Nadu, 36 Telangana, 37 Andhra Pradesh. A business registered in five states has five GSTINs with five different prefixes.
PAN (characters 3-12)
The holder's Permanent Account Number: five letters, four digits, one letter. The 4th letter is the holder type: P individual (so a proprietorship), C company, F firm or LLP, H Hindu Undivided Family, A association of persons, T trust, B body of individuals, L local authority, J artificial juridical person, G government. The 5th letter is usually the first letter of the surname or name.
Entity number (character 13)
How many registrations the same PAN has in the same state: 1 for the first, 2 for the second, and after 9 the letters A to Z.
Z and the check digit (characters 14-15)
The 14th character is Z for regular taxpayers. The 15th is a checksum computed from the first 14 characters using a mod-36 method; it exists to catch typing mistakes.
Worked example
| GSTIN | Reading |
|---|---|
| 27AAPFU0939F1ZV | Maharashtra, a firm with PAN AAPFU0939F, first registration in the state, check digit V |
| 29AAGCB7383J1Z4 | Karnataka, a company (4th PAN letter C), first registration in the state |
If a buyer in Chennai gives you a GSTIN starting 27, either the registration is for a Maharashtra branch or the number is wrong. If a "Private Limited" company gives you a PAN with P as the 4th letter, that PAN belongs to an individual. Both are reasons to check before you bill. Paste any GSTIN into the GSTIN validator to see each part and the expected check digit.
What the format cannot tell you
A correctly formed GSTIN can still be cancelled, suspended or belong to a business other than the one ordering from you, and anyone can calculate a valid check digit. The format is the first filter, not the answer. For the live record use Search Taxpayer on the GST portal:
- Open www.gst.gov.in. You do not need to log in.
- Go to Search Taxpayer, then Search by GSTIN/UIN.
- Enter the 15-character GSTIN, type the captcha and click Search.
- Read the result: legal name, trade name, effective date of registration, constitution of business, GSTIN/UIN status, taxpayer type, administrative office, principal place of business and nature of business activities.
- Click Show Filing Table to see which returns were filed, for which period and on what date.
Or use FundRaksha Trust, which shows the status, names and filing record together. Read how to check a GST number is active.
Why suppliers should read the GSTIN before giving credit
The GSTIN tells you the buyer's state (and therefore whether to charge IGST or CGST plus SGST), its legal form and its PAN. A mismatch between the form in the GSTIN and the name on the order, or a state that does not match the delivery address, is a cheap early warning. Catching it before delivery costs nothing; finding it after the invoice is overdue makes recovery harder because you first have to establish who the buyer is.
Last reviewed: 2026-10-21. Information for Indian businesses; not legal advice.