GST calculator with the CGST, SGST and IGST split

Multiply the price by the rate and add it on: GST = price × rate ÷ 100, and total = price + GST. ₹1,000 at 18% is ₹180 of GST and ₹1,180 in total.

Divide by one plus the rate: price before tax = amount ÷ (1 + rate ÷ 100). The GST is the difference. ₹1,180 including 18% GST is ₹1,000 plus ₹180 of GST. Taking 18% off ₹1,180 directly would give the wrong answer.

A supply within one state (intra-state) is taxed as CGST plus SGST, each at half the rate. For a Union Territory without its own legislature, UTGST replaces SGST. A supply between states, an import or an export (inter-state) carries IGST at the full rate.

Since the rate rationalisation that took effect on 22 September 2025, most goods and services fall under 5% or 18%, with 40% for a short list of luxury and sin goods, and special rates such as 3% for gold and 0.25% for rough diamonds. Rates depend on the HSN or SAC code of what you sell, so confirm yours in the official rate schedules. Use Custom for any other rate, including 12% or 28% on older invoices.

Each figure is shown to two decimal places (paise). CGST and SGST are each half of the total tax, so an odd paisa can appear in rounding. Invoices usually round the final total to the nearest rupee as a separate round-off line.