GST for New Businesses: When You Need It and What to Expect
When GST registration becomes mandatory, when it is optional, what the composition scheme is, and what monthly filing actually involves.
7 min readUpdated 1 September 2026By the Yatharthbiz team
Goods and Services Tax is the indirect tax you charge on most sales of goods and services in India. Once registered, you collect GST from customers, claim credit for the GST you paid on business purchases, and pay the difference to the government through periodic returns.
When registration is mandatory
Registration becomes compulsory when your aggregate turnover crosses a threshold. The threshold is different for goods and for services, and is lower in certain special-category states. Regardless of turnover, registration is required from the start in several common situations:
- You supply goods to customers in another state.
- You sell through an e-commerce operator such as a marketplace.
- You are required to pay tax under reverse charge.
- You are a casual or non-resident taxable person, or an agent supplying on behalf of others.
When voluntary registration makes sense
- Your customers are businesses that want to claim input credit on your invoices.
- You buy a lot of taxable inputs and want to recover the GST on them.
- You plan to sell interstate or online soon and want to be ready.
- Credibility matters in your market — a GSTIN signals a formal business.
The trade-off is administration: once registered, you must file returns on schedule even in months with no sales.
The composition scheme
Small businesses under a turnover limit can opt for the composition scheme: a lower flat rate of tax on turnover, simpler quarterly returns, and no input tax credit. It suits small local traders, manufacturers and restaurants that sell mostly to consumers within their state. It does not suit businesses that sell interstate, sell online or have business customers who need credit.
What filing involves
| Return | What it covers | Frequency |
|---|---|---|
| GSTR-1 | Details of your outward supplies (sales invoices) | Monthly, or quarterly for eligible small taxpayers |
| GSTR-3B | Summary return with tax payment | Monthly, or quarterly under the QRMP scheme |
| GSTR-9 | Annual return consolidating the year | Annually |
| CMP-08 / GSTR-4 | Composition scheme statement and return | Quarterly and annually |
Swipe sideways to see every column.
Behind each return is reconciliation: your purchase invoices must match what your suppliers have filed for you to claim credit. This is where most GST problems start — and why we prefer to keep the books and file the returns as one process.
Mistakes that cause notices
- Claiming input credit on invoices your supplier never filed.
- Charging the wrong rate or the wrong type of tax (CGST/SGST versus IGST) on interstate sales.
- Missing returns in nil-sales months and accumulating late fees.
- Mismatches between GST turnover and the income declared in your income tax return.
- Not updating the registration when you add a location, change your address or add a partner.