A GSTIN, or Goods and Services Tax Identification Number, is the unique 15-character alphanumeric code assigned to every business registered under GST in India. It is made up of the two-digit state code, the business's 10-character PAN, an entity number, the letter Z and a check character, and must appear on every tax invoice.
Why it matters for an Indian small business
Without a GSTIN a business cannot issue a tax invoice, claim input tax credit on purchases, sell on Amazon, Flipkart or most B2B marketplaces, or supply to companies that need credit on their purchases. Registration is mandatory once turnover crosses ₹40 lakh for goods (₹20 lakh in special category states) or ₹20 lakh for services, and for anyone selling across state lines through an e-commerce platform regardless of turnover. Many businesses register voluntarily below the threshold because corporate customers insist on it.
The number also signals legitimacy: displaying the GSTIN on a website, invoices and the Google Business Profile reassures buyers, and a GSTIN validator lets them confirm it in seconds.
How it works
Reading a GSTIN: the first two digits are the state code (24 is Gujarat, 27 Maharashtra, 29 Karnataka, 07 Delhi). Characters three to twelve are the PAN of the proprietor, firm or company. The thirteenth is the number of registrations the PAN holds in that state (usually 1). The fourteenth is Z by default, and the fifteenth is a checksum that validators use to catch typos.
Applying is free on the GST portal: submit PAN, Aadhaar, business address proof, bank details and photographs, complete Aadhaar authentication, and the number is usually issued within three to seven working days after any physical verification. Once registered you file monthly or quarterly returns (GSTR-1 and GSTR-3B) even for nil turnover, so register only when ready to comply.
Example: a Lucknow chikankari boutique
Nazakat Chikan in Hazratganj sells embroidered kurtas in-store and wants to list on Myntra and ship to customers in Mumbai and Hyderabad. Inter-state e-commerce sales require GST registration regardless of turnover, so the owner applies with her PAN, Aadhaar, the shop's electricity bill and a cancelled cheque. The GSTIN arrives in five days, beginning with 09 for Uttar Pradesh. She adds it to her website footer and invoices, the marketplace onboarding clears, and corporate clients ordering 200 kurtas for a conference can now claim input credit on her ₹1.2 lakh invoice, which closes the deal.
Common mistakes
- Registering before you are ready to file returns every month, then accumulating late fees.
- Quoting a GSTIN on invoices from a different state's registration.
- Typing errors that make the checksum fail, so buyers cannot claim credit.
- Not displaying the GSTIN and registration certificate at the business premises, which is required.
- Assuming a GSTIN is the same as a Udyam number or PAN.
How Neweb handles it
Neweb shows your GSTIN in the site footer and legal pages, includes it in Organization schema, issues GST-compliant invoices for your subscription so you can claim input credit, and links to the free GSTIN validator for customers who want to verify you.
GSTIN questions
What is the format of a GSTIN?
Fifteen characters: two-digit state code, ten-character PAN, one entity digit, the letter Z and a check character, for example 27ABCDE1234F1Z5.
Who needs a GSTIN in India?
Businesses with turnover above ₹40 lakh for goods or ₹20 lakh for services (₹20 lakh and ₹10 lakh in some special category states), anyone selling inter-state via e-commerce, and anyone who wants to issue tax invoices or claim input credit.
How much does GST registration cost?
Nothing on the government portal. Consultants charge ₹500 to ₹3,000 to handle the paperwork, and returns filing is an ongoing cost.
Is GSTIN the same as GST number?
Yes. GST number is the common name for the GSTIN.
How do I verify a GSTIN?
Enter it on the GST portal search or a free validator. It shows the registered name, state, status and registration type so you can confirm an invoice is genuine.
Related terms.
Related pages.
GSTIN validator
Check the format and checksum of any GST number instantly.
GST registration process explained
Documents, steps and timelines for getting a GSTIN.
GST basics for small businesses
Thresholds, composition scheme and what to show on your site.
GST calculator
Work out CGST, SGST and IGST on any amount.
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