Almost everyone knows there is a turnover threshold for GST registration. Far fewer know that several categories of business have to register from their first invoice regardless of turnover — and that being in one of those categories is the most common reason a registration turns out to be overdue rather than upcoming.
The turnover thresholds
For most of India, the aggregate turnover threshold is ₹40 lakh for a business supplying goods and ₹20 lakh for one supplying services.
In the special category states those figures are lower — ₹20 lakh for goods and ₹10 lakh for services. Tamil Nadu is not a special category state, so a business there reads the first pair.
Two details matter more than the numbers. Aggregate turnover is computed across all your GSTINs on one PAN and includes exempt supplies, so it is usually larger than the figure a founder has in mind. And once you cross, you have 30 days to apply — the clock starts at the crossing, not at the point you notice it.
The cases where turnover is irrelevant
Some businesses must register from the first rupee. If you are in one of these categories, the thresholds above simply do not apply to you:
- Interstate suppliers of goods — selling across a state border, not merely shipping within Tamil Nadu.
- Sellers on e-commerce marketplaces, and the operators of those marketplaces.
- Anyone required to pay tax under reverse charge on their inward supplies.
- Casual and non-resident taxable persons — including a business exhibiting or supplying temporarily in another state.
- Agents supplying on behalf of another taxable person, and input service distributors.
What the application itself involves
Registration is applied for in GST REG-01 on the GST portal, and the certificate issued is GST REG-06. With Aadhaar authentication completed successfully, registration is generally granted within 7 working days; without it, the timeline stretches to up to 30 days because physical verification enters the picture.
Where biometric authentication is triggered, the applicant has 15 days to complete it at a designated centre. Missing that window is a common cause of an application lapsing quietly rather than being rejected outright.
The cost of registering late
Operating without a registration you were required to hold carries a penalty of ₹10,000 or the tax due, whichever is higher. The larger practical cost is usually different: you cannot issue a tax invoice, so your business customers cannot claim input tax credit on what they bought from you, and you cannot claim credit on your own purchases for the unregistered period either.
That is why the answer to "should I register before I have to?" is often yes for a B2B business — voluntary registration is available, and buyers frequently prefer a registered supplier for exactly that reason.
If you are not sure which side of the line you are on — particularly if you sell interstate or through a marketplace — send us your turnover and how you sell, and we will tell you whether registration is already due.
