The rate
The standard rate in India is 18%. Some goods and services carry reduced or zero rates and others are exempt. The difference matters: zero-rated sales still let you reclaim the tax on your purchases, exempt sales do not.
Since 22 September 2025 GST runs two main slabs, 5% and 18%, with a 40% rate on a short demerit list. The 12% and 28% slabs were abolished. 18% remains the common rate for services.
Who must register
Registration becomes compulsory once taxable turnover passes the threshold Central Board of Indirect Taxes and Customs (CBIC) sets, measured over a rolling period. Below it, registration is usually voluntary, which makes sense if your customers are registered businesses that can reclaim what you charge.
GST registration is compulsory above ₹40 lakh turnover for goods (₹20 lakh in special category states) and ₹20 lakh for services (₹10 lakh in special category states); inter-state and e-commerce sellers must register regardless.
How to register
Register with Central Board of Indirect Taxes and Customs (CBIC) on GST portal (gst.gov.in) and the Income Tax e-filing portal using your GSTIN. Once registered you receive a GST registration number or certificate, and from that date you must charge GST on taxable sales, issue compliant invoices and file returns even when nothing is due.
Charging GST on an invoice
Show the net amount, the GST rate, the GST amount and the gross total, with your registration number in the header. Prices quoted to consumers should include GST; prices quoted to businesses usually exclude it and say so. The India calculator adds or removes GST and shows the arithmetic.
- Tax invoice with the GSTIN of supplier and registered recipient, HSN or SAC code per line, place of supply, and CGST/SGST or IGST shown separately.
- Businesses above ₹5 crore turnover must generate an IRN and QR code through an Invoice Registration Portal.
Filing and paying
Returns are periodic, most often monthly or quarterly, and report the GST you charged less the GST you paid on purchases. The difference is paid to Central Board of Indirect Taxes and Customs (CBIC) by the return deadline; a repayment is claimed when purchases exceed sales.
GSTR-1 (sales) by the 11th and GSTR-3B (summary and payment) by the 20th of the following month; small taxpayers may file quarterly under QRMP. Annual GSTR-9 by 31 December.
Penalties for getting it wrong
Late registration, late returns and late payment each attract penalties and interest with Central Board of Indirect Taxes and Customs (CBIC). Charging GST while unregistered is an offence in most countries. If you missed the threshold, register now and declare the back period.
Late fee of ₹50 a day (₹20 for nil returns) per return plus 18% interest on tax paid late.