What is GSTIN (GST Identification Number)

GSTIN is the 15-digit number the GST system gives every registered taxpayer. It identifies your business on invoices, returns and the GST portal. Each state where you register gets its own GSTIN, built from the state code and your PAN. You receive it once your GST registration is approved.

Why GSTIN matters for your business

Without a GSTIN you cannot charge GST or pass on tax credit to your customers. Buyers also ask for it before they deal with you, because they need your GSTIN on the invoice to claim credit. Banks, marketplaces and large clients often check it as a basic sign that the business is registered and compliant.

How a GSTIN is built

• Digits 1-2: state code (for example, 07 is Delhi).
• Digits 3-12: the PAN of the business or proprietor.
• Digit 13: a number counting registrations under the same PAN in that state.
• Digit 14: the letter Z by default.
• Digit 15: a check character that catches typing errors.

So a company with one PAN and offices in three states will hold three GSTINs, all sharing the same middle ten characters.

Where you need to show or use it

• Tax invoices, credit notes and debit notes.
• Every GST return filing on the portal.
• E-way bills for moving goods, see e-way bill rules.
• Purchase orders, contracts and vendor forms asked for by your customers.

How to get or check a GSTIN

You apply on the GST portal with your PAN, mobile number, email, business address proof, bank details and photographs of the signatory. The portal first issues a temporary reference number; the GSTIN follows after the officer approves the application. To check someone else’s GSTIN, use the “Search Taxpayer” option on the GST portal, which shows the legal name, status and registration date.

Common mistakes

• Typing the wrong GSTIN on a customer’s invoice, so the buyer cannot claim credit.
• Using the GSTIN of one state for sales made from another state’s registration.
• Not checking whether a supplier’s registration is active before paying them.
• Ignoring a cancelled or suspended registration. If you want to close a registration properly, look at GST cancellation.

Related guides: PAN Card explained, GSTR-1 and GSTR-3B, GST due dates calendar

FAQs

How many digits does a GSTIN have?

Fifteen. Two for the state, ten for the PAN, one for the entity count, one fixed letter Z and one check character.

Can one business have more than one GSTIN?

Yes. A business needs a separate registration in each state where it has a place of business, so it holds one GSTIN per state under the same PAN.

Is GSTIN the same as the GST registration certificate?

No. The GSTIN is the number. The certificate is the document issued on approval that shows your GSTIN, legal name and address.

Not sure which registrations your business needs? Talk to a Taxhint expert and we will sort it out with you.