How to Look Up a GST Number in India (GSTIN Verification Guide)

What is a GSTIN?

GSTIN stands for Goods and Services Tax Identification Number. It is a 15-character alphanumeric code assigned to every GST-registered business in India. Think of it as a business's GST identity — unique, permanent, and publicly verifiable.

Understanding what a GSTIN contains and how to verify it is essential for any business that deals with other registered businesses. Accepting an invoice with an invalid or fake GSTIN means you cannot claim Input Tax Credit (ITC) — a costly mistake.

How to Read a GSTIN

A GSTIN follows a fixed 15-character format. Each part carries specific information:

• Characters 1-2 (State Code): Two-digit code for the state of registration. 24 = Gujarat, 27 = Maharashtra, 07 = Delhi, 33 = Tamil Nadu, etc.
• Characters 3-12 (PAN Number): The 10-character PAN of the business or individual
• Character 13 (Entity Number): Number of registrations under the same PAN in the same state (usually 1)
• Character 14 (Default Z): Always Z by default
• Character 15 (Check Digit): Alphanumeric check digit for validation

Example: 24AABCU9603R1ZX — State: Gujarat (24), PAN: AABCU9603R, Entity: 1, Default: Z, Check: X

How to Verify a GSTIN Online

Method 1: GST Portal (Official)

1. Go to gst.gov.in
2. Click Search Taxpayer in the top menu
3. Select Search by GSTIN/UIN
4. Enter the 15-character GSTIN
5. Complete the CAPTCHA and click Search

The result shows: legal name, trade name, registration date, business type, and current status (Active/Cancelled/Suspended).

Method 2: CBIC Portal

The Central Board of Indirect Taxes and Customs (CBIC) also provides GSTIN search at cbic-gst.gov.in. Same information, alternative source.

Method 3: Billing Software Auto-Lookup

The most efficient method for businesses that create many invoices. In InfiBis, enter a customer's GSTIN and the system automatically fetches and fills their legal name, trade name, and registered address. No manual typing, no errors.

What to Check When Verifying a GSTIN

Do not just check that the GSTIN exists. Verify these four things:

1. Status is Active — a cancelled or suspended GSTIN cannot issue valid tax invoices
2. Legal name matches — the name on the invoice should match the registered legal name
3. State code matches — the first two digits should match the state where the business operates
4. Registration date — invoices dated before the registration date are invalid

Common GSTIN Errors and How to Avoid Them

Transposed Characters

The most common error. A GSTIN like 24AABCU9603R1ZX can easily become 24AABCU9630R1ZX when typed manually. Always copy-paste or use auto-fill from billing software.

Wrong State Code

A business registered in Maharashtra (27) cannot issue invoices with a Gujarat (24) GSTIN. If the state code doesn't match the supplier's location, something is wrong.

Using a Cancelled GSTIN

Businesses that close or deregister have their GSTIN cancelled. Invoices from a cancelled GSTIN are invalid for ITC purposes. Always verify status before accepting large invoices.

Fake GSTINs

Unfortunately, fake GSTINs exist. They may pass a format check but fail on the GST portal. Always verify on the official portal for new suppliers, especially for high-value transactions.

GSTIN Lookup in Your Billing Workflow

For businesses that create many B2B invoices, manual GSTIN verification is impractical. The right approach:

1. When adding a new customer, enter their GSTIN in your billing software
2. The software fetches their details from the GST portal automatically
3. Review and confirm — the name and address are pre-filled
4. All future invoices for this customer use the verified GSTIN

This takes 10 seconds instead of 5 minutes and eliminates manual errors entirely.

GST Registration Status Types

• Active: Valid registration, can issue and receive GST invoices
• Cancelled: Registration voluntarily surrendered or cancelled by department. Cannot issue GST invoices.
• Suspended: Temporarily suspended, usually pending compliance action. Invoices during suspension period are risky.
• Provisional: Temporary registration during migration. Rare now.

What Happens if You Accept an Invoice with Invalid GSTIN?

If you claim ITC based on an invoice with an invalid, cancelled, or fake GSTIN:

• The ITC claim will be rejected during GSTR-2A reconciliation
• You will need to reverse the ITC and pay the tax amount with interest
• In cases of deliberate fraud, penalties can apply

The cost of verifying a GSTIN: 10 seconds. The cost of not verifying: potentially lakhs in rejected ITC.

Conclusion

GSTIN verification is a non-negotiable step in any B2B transaction. Use the GST portal for one-off checks, and use billing software with built-in GSTIN auto-fill for your regular invoicing workflow. InfiBis handles GSTIN lookup automatically so every invoice is accurate from the start. For a complete guide to GST invoicing, read how to create a GST invoice in India.