GSTIN: Format, How to Verify Any GST Number Online & Decode What It Means (2025)
Every GST-registered business in India has a GSTIN — a 15-digit alphanumeric code that serves as the unique identifier for all their GST transactions. It appears on every invoice, every GST return, and every ITC claim.
- GSTIN is a unique 15-digit alphanumeric code assigned to every GST-registered business, derived from their PAN.
- The first 2 digits are the state code, digits 3-12 are the PAN, digit 14 is always 'Z', and digit 15 is a check code.
- The GST portal (gst.gov.in) is the only 100% authoritative source to verify a GSTIN's status, name, and registration type.
- A Composition scheme dealer cannot legally charge GST — if they do, that ITC cannot be claimed.
- Claiming ITC on an invoice with a fake or cancelled GSTIN leads to ITC reversal plus 24% p.a. interest, even though the fraud was the supplier's.
- A structurally fake GSTIN can often be spotted instantly — wrong character count, invalid state code, or digit 14 not being 'Z'.
But here's what surprises many businesses: you should never trust a GSTIN you haven't verified. Fake GSTINs are used to generate fraudulent invoices for bogus ITC claims. If you buy from a supplier with a fake or cancelled GSTIN and claim ITC on that invoice, the ITC will be disallowed and you'll face a demand notice — even though you were the victim.
This guide explains what GSTIN is, how to read its 15-digit structure, and how to verify any GSTIN in 30 seconds using the official government portal.
What Is GSTIN?
GSTIN stands for Goods and Services Tax Identification Number. It is a unique 15-digit alphanumeric code assigned to every person or entity that registers under the GST Act.
GSTIN is:
- Mandatory on all tax invoices — your GSTIN and the buyer's GSTIN must appear on every B2B invoice
- Required for filing GST returns — GSTR-1, GSTR-3B, and all other returns are filed under your GSTIN
- Linked to your PAN — the structure of GSTIN is derived from your PAN
- State-specific — if you operate in multiple states, you get a separate GSTIN for each state
- Public information — any person can look up any GSTIN on the government portal
What Does Each Digit of a GSTIN Mean?
A GSTIN looks like this: 27AABCU9603R1ZX
Let's decode it position by position:
| Position | Digits | Meaning | Example |
|---|---|---|---|
| 1–2 | Digits 1-2 | State Code (2-digit Indian state/UT code) | 27 = Maharashtra |
| 3–12 | Digits 3-12 | PAN of the taxpayer (10 characters, alpha-numeric) | AABCU9603R |
| 13 | Digit 13 | Entity number — serial number of GST registrations under the same PAN in the same state | 1 (first registration) |
| 14 | Digit 14 | 'Z' by default — always the letter Z | Z |
| 15 | Digit 15 | Check code — alpha or numeric, used for error detection | X |
State Codes Reference
| Code | State | Code | State |
|---|---|---|---|
| 01 | Jammu & Kashmir | 18 | Assam |
| 02 | Himachal Pradesh | 19 | West Bengal |
| 03 | Punjab | 20 | Jharkhand |
| 04 | Chandigarh | 21 | Odisha |
| 06 | Haryana | 22 | Chhattisgarh |
| 07 | Delhi | 23 | Madhya Pradesh |
| 08 | Rajasthan | 24 | Gujarat |
| 09 | Uttar Pradesh | 27 | Maharashtra |
| 10 | Bihar | 29 | Karnataka |
| 11 | Sikkim | 32 | Kerala |
| 12 | Arunachal Pradesh | 33 | Tamil Nadu |
| 13 | Nagaland | 36 | Telangana |
| 14 | Manipur | 37 | Andhra Pradesh |
| 15 | Mizoram | 96 | Foreign country (for OIDAR) |
| 16 | Tripura | 97 | Other Territory |
| 17 | Meghalaya |
What the state code tells you: The first 2 digits of any GSTIN reveal the state where the supplier is registered. If a Maharashtra-based supplier gives you a GSTIN starting with 29 (Karnataka), something is wrong. Cross-check the state code against the billing address.
Reading the PAN in GSTIN
Digits 3–12 of the GSTIN are exactly the taxpayer's PAN. This means:
- You can cross-verify the PAN against the GSTIN
- If a supplier's PAN doesn't match digits 3-12 of their GSTIN, the GSTIN is fake
- The 4th character of PAN reveals the entity type:
P= Individual,C= Company,H= HUF,F= Firm,T= Trust,B= Body of Individuals
Example: GSTIN 27AABCU9603R1ZX — PAN is AABCU9603R, 4th character is C → this is a company registered in Maharashtra.
How to Verify a GSTIN Online: Official Methods
Method 1 — GST Portal (gst.gov.in) — Most Reliable
Go to gst.gov.in
Click Search Taxpayer in the top menu
Select Search by GSTIN/UIN
Enter the 15-digit GSTIN and complete the CAPTCHA
Click Search
The portal displays:
- Legal name of the business
- Trade name (if different)
- Registration type (Regular / Composition / IGST / TDS / TCS)
- Registration status (Active / Cancelled / Suspended)
- Date of registration
- State and jurisdiction
- Principal place of business
- Business constitution (proprietor, company, LLP, etc.)
This is the only 100% authoritative source. All other tools (ClearTax, Razorpay, etc.) fetch data from the same GSTN database — but the portal is the original source.
Method 2 — Search by PAN
If you have the taxpayer's PAN but not their GSTIN:
Go to gst.gov.in → Search Taxpayer → Search by PAN
Enter the PAN
All GSTINs registered under that PAN (across all states) are listed
This is useful for verifying whether a supplier has active registrations in the states where they claim to operate.
Method 3 — Search by Name
Go to gst.gov.in → Search Taxpayer → Search by Legal Name / Trade Name
Enter the business name
The portal returns all matching registrations
Useful when you have the business name but not the GSTIN.
What Should You Check When You Verify a GSTIN?
Don't just check if the GSTIN exists — check all of this:
| What to Check | Why It Matters |
|---|---|
| Status: Active? | A cancelled or suspended GSTIN cannot issue valid tax invoices |
| State matches billing address? | State code (digits 1-2) must match where goods/services are supplied from |
| Business name matches invoice? | The legal name on the portal must match the invoice |
| Registration type | If listed as "Composition Dealer", they cannot charge GST on invoices — any GST charged is illegal |
| Date of registration | Invoice date must be after the registration date |
The Composition Dealer Trap
This is one of the most common fraudulent invoicing patterns:
- A Composition scheme taxpayer cannot charge GST on their outward supplies
- If a composition dealer issues you a GST invoice charging 18% CGST + SGST, they are doing so illegally
- You cannot claim ITC on such an invoice — the GST Council has clarified this explicitly
- Always check the registration type on the portal before accepting invoices from small suppliers
How Do You Spot a Fake GSTIN Before You Even Verify?
A quick structural check can flag obvious fakes:
Count the characters — Must be exactly 15. 14 or 16 characters = fake
Check digit 1-2 — Must be a valid state code (01–37, 96, 97, 99). If it's 00, 50, 60, 70, 80, 90 = fake
Check digit 14 — Must always be the letter Z. Any other character = fake
Check digits 3-12 match a valid PAN format — PAN format is: 5 letters, 4 digits, 1 letter (e.g., AABCU9603R). If digits 3-12 don't follow this pattern = fake
Example of an obviously fake GSTIN: 99ABCDE12341ZX — state code 99 doesn't exist, and PAN format ABCDE1234 is wrong (should be 5 letters, 4 digits, 1 letter).
Why GSTIN Verification Matters for ITC Claims
This is the practical reason verification is non-negotiable:
If you accept an invoice from a supplier with a cancelled or fake GSTIN and claim ITC on it:
The GSTIN won't appear in your GSTR-2B (because the supplier can't file returns with an invalid GSTIN)
The department will notice the mismatch between your ITC claim and your GSTR-2B
You'll receive a GST notice demanding reversal of ITC plus 24% p.a. interest
You may also face a Section 122 penalty
The loss is yours even though the fraud was the supplier's. This is why verification before transactions — not after — is the only safe approach.
Can a Business Have Multiple GSTINs Under One PAN?
A business operating in multiple states must register separately in each state — meaning multiple GSTINs under the same PAN.
Example: A company with operations in Delhi, Maharashtra, and Karnataka will have 3 GSTINs:
07+ PAN + entity code (Delhi)27+ PAN + entity code (Maharashtra)29+ PAN + entity code (Karnataka)
When verifying such a supplier, use "Search by PAN" to see all active registrations. If they invoice you from a Maharashtra address but you can only find a Delhi GSTIN, they may not have Maharashtra registration — creating ITC risk for you.
GSTIN for Special Cases
Unregistered Persons (URD)
If your supplier is unregistered (below GST threshold), no GSTIN exists. You handle the GST under Reverse Charge Mechanism (RCM) in some cases. See our Reverse Charge Mechanism guide for details.
Government Departments (GD) and PSUs
Government bodies have UIN (Unique Identification Number) instead of GSTIN. Format is similar (15 characters) but starts with the state code and has D for government department.
Non-Resident Taxable Persons
NRTPs operating in India temporarily have GSTINs starting with 99 (special code for non-residents).
Using GSTIN in GSTR-1 Filing
When filing GSTR-1, you must enter the buyer's GSTIN for every B2B invoice in Table 4. An incorrect GSTIN in GSTR-1 means:
- The invoice doesn't appear in the buyer's GSTR-2B
- The buyer cannot claim ITC
- The buyer will chase you for a correction
- You'll need to amend in the next period's GSTR-1
Always verify the GSTIN before entering it in GSTR-1. A single digit error causes significant downstream compliance problems.
For the complete GSTR-1 filing walkthrough, see our How to File GSTR-1 guide.
External References
gst.gov.in Search Taxpayer — official GSTIN verification
CBIC GSTIN format rules — official format specification
GSTN database — the underlying data source for all GSTIN lookups
Conclusion
GSTIN verification is a 30-second task that can save you from significant ITC losses and compliance notices. Your checklist for every new supplier:
Verify GSTIN is Active on gst.gov.in
Check state code matches supplier's location
Confirm legal name matches the invoice
Check registration type — reject invoices from Composition dealers charging GST
Verify registration date is before the invoice date
For multi-state suppliers, search by PAN to see all active registrations
Build this into your procurement and accounts payable workflow. A fake or cancelled GSTIN discovered after 6 months of invoices means 6 months of ITC to reverse — plus interest.
Related: Input Tax Credit Under GST · GST Invoice Format India · GST Registration Process India · Reverse Charge Mechanism GST
GSTIN Verification — Frequently Asked Questions
How many digits does a valid GSTIN have?
Exactly 15 alphanumeric characters. Any GSTIN with 14 or 16 characters is fake.
What does the 14th digit of a GSTIN represent?
It is always the letter 'Z' by default — any other character at this position indicates a fake or malformed GSTIN.
Where can I verify a GSTIN for free?
On the official GST portal at gst.gov.in, under Search Taxpayer → Search by GSTIN/UIN. It is the only 100% authoritative source.
Can I claim ITC on an invoice from a Composition dealer charging GST?
No. Composition scheme taxpayers cannot legally charge GST on their supplies, so ITC cannot be claimed even if GST appears on the invoice.
What happens if I claim ITC on an invoice with a cancelled GSTIN?
The ITC will be disallowed once the mismatch with your GSTR-2B is detected, and you will face a demand notice for reversal plus 24% per annum interest.
Verify the GSTIN, then verify the GST
After you confirm the supplier on gst.gov.in, use the calculator to double-check the tax on each invoice.
Open the Free GST Calculator India →