Registration becomes mandatory once aggregate turnover crosses ₹40 lakh for goods (₹20 lakh for services) in a normal state, under s.22 of the CGST Act 2017 — with special-category states at ₹20 lakh for goods and ₹10–20 lakh for services per the 28th GST Council decisions. This checker applies the right threshold for your state category.

Yes — any person making an interstate taxable supply must register regardless of turnover, under s.24(i) of the CGST Act 2017. There is no threshold exemption for interstate supplies, so even a pre-revenue business with one out-of-state customer must register.

No. Online Information and Database Access (OIDAR) service providers and e-commerce operators are compulsorily registrable with no threshold exemption, under s.24(xi) of the CGST Act 2017. A SaaS or marketplace business must register from the first rupee of taxable supply.

The Composition Scheme under s.10 of the CGST Act 2017 lets eligible small taxpayers pay tax at a flat rate on turnover instead of the standard rate — 1% for traders, 5% for restaurants, 0.5% for manufacturers, and 6% for services under s.10(2A) — with a turnover cap of ₹1.5 crore for goods and ₹50 lakh for services. Composition taxpayers cannot claim input tax credit or make interstate supplies.

Registered businesses must file GSTR-3B (summary return with tax payment) monthly or quarterly under QRMP, GSTR-1 (outward supplies) monthly or quarterly, and GSTR-9 (annual return) by 31 December — each under the CGST Act 2017 rules. E-invoicing applies above ₹5 crore aggregate turnover and e-way bills are needed for goods movement above ₹50,000 in value.