GST Registration in Tamil Nadu: Who Must Register and the Turnover Limits

Updated 29 October 2026

Most businesses must register under GST once their turnover crosses a set limit, but some must register from their very first sale. This guide explains the limits that apply in Tamil Nadu, the cases where turnover does not matter, and what the application involves.

The turnover limits in Tamil Nadu

Tamil Nadu is a normal category state, so these limits apply:

• ₹40 lakh a year, if you supply only goods (some goods, such as pan masala and tobacco products, are excluded and fall under the ₹20 lakh limit)
• ₹20 lakh a year, if you supply services, or both goods and services

Once your aggregate turnover crosses the limit in a financial year, you must apply for registration within 30 days.

What counts as aggregate turnover

Aggregate turnover is worked out for your PAN across all of India, not per shop or per state. It includes:

• Taxable sales of goods and services
• Exempt supplies (for example, fresh vegetables or certain services)
• Exports and other zero-rated supplies
• Inter-state supplies between your own branches under the same PAN

It does not include the GST itself, or purchases on which you pay tax under the reverse charge.

When you must register whatever your turnover

Section 24 of the CGST Act requires registration from the first sale in these cases, among others:

• You sell goods to buyers in another state (inter-state supply of goods)
• You are liable to pay tax under the reverse charge
• You are a casual taxable person or a non-resident taxable person
• You sell goods through an e-commerce platform, except where the relief for small sellers within the state applies
• You are required to deduct TDS or collect TCS under GST, or you act as an Input Service Distributor

Service providers who make inter-state supplies of services can stay unregistered while their aggregate turnover is within ₹20 lakh.

Voluntary registration

You can register even if your turnover is below the limit. Businesses often do this because larger customers prefer to buy from registered suppliers, or to claim input tax credit on purchases. Once registered, you must file returns every month or quarter, even when there are no sales.

How to apply

• Apply online on the GST portal (gst.gov.in) in Form GST REG-01
• Part A: PAN, mobile number and email, verified by OTP
• Part B: business details, place of business, bank account and the documents listed in our GST registration checklist
• Aadhaar authentication of the proprietor, partners or directors; some applicants are asked to visit a GST Suvidha Kendra for photo and biometric verification
• The officer may ask for clarification (Form REG-03); once approved, the certificate (Form REG-06) can be downloaded from the portal

After registration

Registration brings regular filing: GSTR-1 for sales and GSTR-3B for the tax payable, monthly or quarterly, and an annual return for larger businesses. Small businesses with turnover up to ₹1.5 crore (₹50 lakh for most service providers) can consider the composition scheme, which has a fixed tax rate and simpler returns but does not allow input tax credit. Our due dates calendar lists the upcoming GST dates.

This guide is general information based on the law as on the date shown above, and is not professional advice. Rules and due dates change, and the right course depends on your facts. Please speak to us before acting on it.