GSTIN Format Checker

What is a GST Number check? A GST number search allows you to verify the 15-digit Goods and Services Tax Identification Number (GSTIN) of any business. Use our tool to instantly validate the format, state code, and PAN offline.

15-character alphanumeric code (e.g. 27AABCU9603R1ZX)

GSTIN Format Explained

27AABCU9603R1ZX
Chars 1–2State code (27 = Maharashtra)
Chars 3–12PAN of the taxpayer (10 characters)
Char 13Entity number (1–9 or A–Z for multiple registrations)
Char 14Always "Z" (reserved)
Char 15Checksum digit (0–9 or A–Z)

Note: This tool validates the GSTIN format and checksum offline. For real-time registration status, visit the official GST portal at gst.gov.in.

Why Verify a GST Number?

Doing a quick GST number check before entering into a transaction is crucial for businesses in India. Fake GST invoices are a common form of tax fraud, where unregistered entities collect tax without depositing it to the government. If you claim Input Tax Credit (ITC) on a fake GST bill, you will face penalties and ITC reversal.

Decoding the GSTIN Structure

The GSTIN is a mathematically structured 15-character alphanumeric code. It contains hidden data about the business:

  • First 2 digits: Represent the state code (e.g., 27 for Maharashtra, 07 for Delhi).
  • Next 10 characters: This is the exact PAN (Permanent Account Number) of the registered taxpayer.
  • 13th character: Indicates the entity number of the same PAN holder within the state.
  • 14th character: Always the letter 'Z' by default.
  • 15th character: The checksum digit. This is mathematically generated using a complex algorithm to ensure the previous 14 characters haven't been typed incorrectly.

GST Number Search By Name vs Offline Validation

If you want to do a GST number search by name or try to find gst number by pan without login, you must use the official GST portal's taxpayer search function to find the exact registration. However, if a supplier has given you their GST number on an invoice, our free online tool to check gst number validity instantly checks its mathematical authenticity without sending any data over the internet.

Do you have a bulk gstin verification tool free?

We are currently building out a bulk gstin verification tool free for accountants and businesses that need to verify hundreds of GSTINs simultaneously. For now, this single-lookup offline tool is the fastest way to decode a PAN and State from any individual GSTIN.

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Frequently Asked Questions

Everything about validating and understanding GSTIN numbers.

What is a GSTIN?
GSTIN (Goods and Services Tax Identification Number) is a unique 15-character alphanumeric code assigned to every GST-registered business in India. It is your primary identity on the GST portal and must appear on all tax invoices, returns, and official communications.
What is the structure of a GSTIN?
A GSTIN is 15 characters long: Characters 1-2 = 2-digit State Code (e.g., 27 for Maharashtra, 07 for Delhi). Characters 3-12 = 10-character PAN of the entity. Character 13 = Entity number (1 for the first registration, 2 for a second, etc.). Character 14 = Always "Z". Character 15 = Checksum digit (alphanumeric).
How do I validate a GSTIN offline?
Our GSTIN Validator checks the number locally without any internet connection. It verifies: (1) total character count is exactly 15, (2) state code is valid (01-38), (3) PAN embedded within is valid format, (4) the checksum digit at position 15 is mathematically correct. No API call is made.
What does the 2-digit state code in GSTIN represent?
The first two digits are the GST State Code. For example: 01 = Jammu & Kashmir, 07 = Delhi, 27 = Maharashtra, 29 = Karnataka, 33 = Tamil Nadu. Our validator automatically decodes the state name from these two digits.
What is the checksum digit in GSTIN?
The 15th character of a GSTIN is a calculated checksum based on a modulus-36 algorithm applied to the first 14 characters. This digit allows offline validation: if the algorithm produces a different character, the GSTIN is invalid. Our validator performs this check instantly.
Can I look up a GSTIN on the government portal?
Yes. You can verify GSTIN details (like legal name, trade name, registration status, and return filing status) on the official GST portal at www.gst.gov.in under the "Search Taxpayer" section. Our offline validator only checks format validity — for live portal data, you must use the official site.
What does entity number 1, 2, 3 in GSTIN mean?
The 13th character (entity number) indicates how many GST registrations a PAN holder has in the same state. "1" means their first registration in that state, "2" is the second (e.g., a second business vertical), and so on up to "9". After "9", the coding switches to letters A, B, C, etc.
Is a GSTIN the same as a GSTN?
No. GSTIN is the Goods and Services Tax Identification Number assigned to a taxpayer. GSTN (Goods and Services Tax Network) is the company/platform that built and operates the GST technology infrastructure. GSTN processes all returns, payments, and registrations; GSTIN is just your tax ID on that platform.
How do I get a GSTIN?
You get a GSTIN by completing GST registration on the GST portal (www.gst.gov.in). The process requires your PAN, Aadhaar, business address proof, bank account details, and business type details. After verification, the GSTIN is issued within 7 working days.
Can a GSTIN become invalid or cancelled?
Yes. A GSTIN can be cancelled if the business: voluntarily surrenders it (e.g., turnover drops below threshold), fails to file returns consecutively, or is found to be fraudulent. After cancellation, the GSTIN shows as "Cancelled" on the portal. Our format validator cannot check live status — always verify active status on the GST portal.