An unverified supplier GSTIN (Goods and Services Tax Identification Number) can cost you your input tax credit and trigger penalties. A fake, cancelled, or mistyped number on an invoice puts your claim at risk. The fix is simple: verify every GSTIN free on the government portal before you pay.
You can do this yourself in under a minute. This post explains what a GSTIN is, how the 15-character format works, how to verify one on the GST portal at gst.gov.in, how to check a supplier by PAN, and why verification protects your input tax credit.
What Is a GSTIN in India?
A GSTIN is a 15-character alphanumeric ID issued to every business registered under the Goods and Services Tax (GST) in India. GST rolled out on 1 July 2017, replacing state VAT and the older TIN (Taxpayer Identification Number), per the Press Information Bureau’s GST launch record. The GSTIN is issued in FORM GST REG-06 under the CGST Act, 2017.
Registration is state-wise and PAN-based. The GSTIN embeds the 10-character PAN (Permanent Account Number) of the business in positions 3 to 12. One PAN can hold multiple GSTINs, one for each state where the business operates. Two authorities run the system: GSTN (Goods and Services Tax Network) operates the portal, and CBIC (Central Board of Indirect Taxes and Customs) administers policy, per CBIC’s official mandate.
Who Needs a GSTIN Registration in India?
Goods suppliers must register once aggregate turnover crosses ₹40 lakh (₹20 lakh in special category states); service providers register above ₹20 lakh (₹10 lakh in special category states). Some categories must register regardless of turnover. Registration is also open voluntarily, which many businesses choose to claim input tax credit and look credible to B2B partners.
| Supplier type / category | Threshold | Source |
|---|---|---|
| Goods suppliers (exclusive supply) | ₹40 lakh (₹20 lakh in special category states) | Notification No. 10/2019-Central Tax, eff. 1 Apr 2019 (GST Council) |
| Service providers | ₹20 lakh (₹10 lakh in special category states) | Section 22, CGST Act, 2017 (CBIC) |
| Inter-state suppliers, e-commerce operators, casual and non-resident taxable persons, reverse charge, input service distributors, agents | Register regardless of turnover | Section 24, CGST Act, 2017 (CBIC) |
Since 1 February 2019, the special category states for these thresholds are Manipur, Mizoram, Nagaland, and Tripura, per the GST Council’s Section 22 notification. The ₹40 lakh goods relief also excludes dealers in ice cream, pan masala, and tobacco.
What Is the GSTIN Format?
A GSTIN is a fixed 15-character structure, standardized within India. It is a 2-digit state code, the 10-character PAN, a 1-character entity number, the letter Z, and a check digit. The format never varies inside India. A worked example is 27ABCDE1234F1Z5.
| Position | Characters | Meaning | Source |
|---|---|---|---|
| 1-2 | 2 digits | State code (Indian Census 2011 list) | GST state code list (GSTN) |
| 3-12 | 10 alphanumeric | PAN of the registered entity | CBIC / FORM GST REG-06 |
| 13 | 1 character | Entity number: 1-9 then A-Z, up to 35 registrations per PAN per state | GSTN format spec |
| 14 | 1 letter | Default “Z”, reserved for future use | GSTN format spec |
| 15 | 1 character | Check digit for error detection | GSTN format spec |
The check digit is computed with a modulo-36 algorithm, so validation tools catch most typos before you ever query the portal.
Which State Codes Appear in a GSTIN?
The first two digits map to a state, based on the Indian Census 2011 code list published by GSTN. Common codes appear below.
| Code | State | Code | State |
|---|---|---|---|
| 06 | Haryana | 27 | Maharashtra |
| 07 | Delhi | 29 | Karnataka |
| 09 | Uttar Pradesh | 33 | Tamil Nadu |
| 19 | West Bengal | 36 | Telangana |
| 24 | Gujarat |
Source: GST state code list (GSTN, based on Indian Census 2011).
What Are Common GSTIN Typos?
Most GSTIN errors are simple entry mistakes, not fraud. Watch for these:
- Missing or extra characters
- Wrong state code
- PAN segment errors
- Wrong or missing check digit
- Transposed adjacent characters
- O/0 and I/1 confusion
- Copy-paste truncation
The check digit algorithm lets a validation tool flag most of these before a portal lookup.
How Do You Check a GSTIN on the GST Portal?
Verification is free at gst.gov.in using the Search Taxpayer tool, with no login required. Go to Search Taxpayer, choose Search by GSTIN/UIN (Unique Identification Number), enter the 15-character GSTIN plus the captcha, and search. GSTN frames this Search Taxpayer utility as protection against vendors using a fake GSTIN.
Steps:
- Open the GST portal at gst.gov.in.
- Click Search Taxpayer, then Search by GSTIN/UIN.
- Type the GSTIN exactly, for example 27ABCDE1234F1Z5.
- Enter the captcha shown on screen.
- Click Search to view the taxpayer record.
The portal returns a defined set of fields. Read them against the invoice in front of you.
| Field returned | What it tells you | Source |
|---|---|---|
| Legal name of business | Registered legal entity | GST portal, Search Taxpayer |
| Trade name | Brand or operating name | GST portal, Search Taxpayer |
| GSTIN status | Active, Cancelled, or Suspended | GST portal, Search Taxpayer |
| Constitution of business | Proprietorship, partnership, private limited | GST portal, Search Taxpayer |
| Taxpayer type | Regular, Composition, SEZ (Special Economic Zone) | GST portal, Search Taxpayer |
| Date of registration | When GST registration took effect | GST portal, Search Taxpayer |
| State and centre jurisdiction | Governing tax offices | GST portal, Search Taxpayer |
| Nature of business activities | Declared activity | GST portal, Search Taxpayer |
How Do You Verify a GSTIN by PAN?
The portal’s Search by PAN feature lists every GSTIN registered under one 10-character PAN across all states. This is how you confirm a multi-state supplier’s full registration footprint in a single lookup, on the same free Search Taxpayer page at gst.gov.in.
Use it during vendor onboarding. If a supplier invoices you from more than one state, Search by PAN shows every GSTIN tied to that PAN. It also lets you confirm that the GSTIN printed on an invoice belongs to the same PAN named on the contract.
Why Does GSTIN Verification Matter for Input Tax Credit Claims?
Input tax credit (ITC) is the GST a buyer offsets against its own output tax. You can claim it only when the supplier holds a valid, active GSTIN and has actually filed returns and paid the tax. A fake or cancelled GSTIN means your ITC gets denied or reversed. This is the single strongest business reason to verify before you pay.
Fake registrations and fake-invoicing rackets are a standing CBIC enforcement priority. Verifying the GSTIN protects you from being caught in a chain you did not create.
How Do GSTR-1, GSTR-2A, and GSTR-2B Affect Your ITC?
GSTR-1 is the supplier’s outward-supplies return. GSTR-2A and GSTR-2B are the buyer-side statements that auto-populate from suppliers’ GSTR-1 filings. If a supplier never files, the invoice never appears in your GSTR-2A or GSTR-2B, and your ITC claim fails reconciliation. Valid status alone is not enough; the supplier has to file.
The portal’s Return Filing Status view shows whether a GSTIN holder files regularly. Build this into verification: check filing behavior, not just Active status. Your GST returns in India are the natural next step once a supplier clears verification.
What Is the Difference Between Regular and Composition Taxpayers?
The taxpayer type field decides whether you get ITC. A Composition scheme dealer (Section 10, CGST Act, 2017) pays a flat rate, cannot charge GST on invoices, and cannot pass on input tax credit. So a buyer earns no ITC from Composition purchases. Regular taxpayers charge GST, and their invoices are creditable.
SEZ taxpayer types also appear in portal results. If the type reads Composition, expect no creditable tax on that vendor’s invoices, and price the relationship accordingly.
How Do You Verify a Supplier GSTIN Before Onboarding in India?
A supplier check is four steps: confirm the GSTIN is Active on the portal, match the legal name and state code to the invoice, confirm the taxpayer type is Regular (Composition dealers cannot pass on ITC), and check Return Filing Status for regular GSTR-1 filing. Clear all four before the first payment.
Re-verify quarterly or before large payments. Status can move from Active to Suspended or Cancelled at any time, and the portal shows only the current status, never the history. A vendor that was clean last quarter may not be clean today.
What Are the Consequences of Using an Invalid GSTIN?
An invalid GSTIN on invoices or returns leads to denied ITC, late fees, interest, and penalties under the CGST Act, 2017. It also blocks e-way bill and e-invoice generation. The core figures are below.
| Default | Charge | Source |
|---|---|---|
| Late filing (return with tax) | ₹50/day (₹25 CGST + ₹25 SGST) | Section 47, CGST Act, 2017 (CBIC) |
| Late filing (nil return) | ₹20/day (₹10 CGST + ₹10 SGST) | CBIC late-fee notifications |
| Interest on unpaid tax | 18% per annum | Section 50, CGST Act, 2017 (CBIC) |
| Interest on excess ITC claimed | 24% per annum | Section 50, CGST Act, 2017 (CBIC) |
| Short payment, no fraud | 10% of tax due, min ₹10,000 | Section 73, CGST Act, 2017 (CBIC) |
| Tax evaded, fraud | 100% of tax, min ₹10,000 | Section 74, CGST Act, 2017 (CBIC) |
| General penalty | up to ₹25,000 | Section 125, CGST Act, 2017 (CBIC) |
Later CBIC notifications also made the maximum late fee turnover-linked for several returns, so caps scale with size. Beyond the money, an invalid GSTIN damages your standing with B2B partners who run their own due diligence.
What Should You Do If a GSTIN Shows Invalid or Inactive?
First rule out typos in the state code, PAN segment, and check digit. Then confirm the registration is processed and active, since a newly issued GSTIN can take time to appear on the portal. Most “invalid” results are entry errors, not fraud.
| Error message | Likely cause | Fix |
|---|---|---|
| Invalid / Not Recognized | GSTIN mistyped or not registered | Re-check each character and re-enter |
| Inactive | Newly issued or deactivated | Allow processing time or confirm activation |
| No Record Found | Not linked to an active account | Confirm the business is registered |
| Mismatch with Records | Details do not match the database | Verify legal name, state code, and PAN |
Unresolved issues go through the GST Self Service Portal, a grievance ticketing system searchable by Ticket Reference Number, GSTIN, or email, or the GST Helpdesk at 1800-103-4786. The self-service portal is for support tickets, not for verification.
Can You Verify GSTINs in Bulk Online?
The official GST portal supports only one GSTIN lookup at a time. Finance teams with hundreds of vendors use third-party tools with CSV upload or API access. ClearTax, Masters India, and Razorpay offer free single-lookup tools with paid bulk tiers, and Commenda supports bulk GSTIN validation across your vendor list.
For teams that also file at scale, ongoing verification pairs naturally with GST software in India that handles returns and reconciliation in one place.
How Commenda Helps With GSTIN Verification and GST Compliance
Verifying one GSTIN is easy. Verifying hundreds every quarter, matching them to invoices, and tracking filing behavior across states is where finance teams lose hours. Commenda’s indirect tax platform validates supplier GSTINs in bulk and tracks GST filing obligations across jurisdictions, so you carry certainty into every vendor payment instead of low-grade doubt.
It fits the wider stack too. Commenda’s Global Tax ID Verification tool checks tax IDs across countries when you onboard cross-border vendors, and Commenda connects to 100+ ERPs, APIs, and custom integrations so verification runs where your data already lives.
Book a demo to see a bulk GSTIN check run on your own vendor list.
