Add GST to a price or take it out of a GST-inclusive amount, with the CGST + SGST split for sales within your state and IGST for sales to another state. Uses the current rates in force since 22 September 2025.
To add GST, multiply the amount by the rate: on ₹1,000 at 18%, GST is ₹180 and the total is ₹1,180.
To remove GST from an inclusive price, divide by (100 + rate) and multiply by 100: ₹1,180 ÷ 118 × 100 = ₹1,000 before GST, so the GST is ₹180.
For a sale within one state (intra-state), the GST is split equally into CGST, which goes to the centre, and SGST (or UTGST in a union territory), which goes to the state. At 18%, that is 9% + 9%.
For a sale to another state (inter-state), the full rate is charged as IGST. Exports and supplies to SEZs are usually zero-rated.
Since 22 September 2025, most goods and services fall in two main slabs, 5% and 18%, with a 40% rate for a short list of luxury and sin goods. The old 12% and 28% slabs were removed, and most items in them moved to 5% and 18%. Some items remain at 0%, and gold, silver and jewellery (3%) and rough diamonds (0.25%) keep their special rates.
The rate for a particular product or service depends on its HSN or SAC code, so check the official GST rate schedule before you bill. For an invoice dated before 22 September 2025, enter the old rate as a custom rate.
Once you know the amounts, BillFlow’s free GST invoice generator adds your GSTIN, the place of supply, HSN/SAC codes and the CGST/SGST or IGST split automatically, and downloads a clean PDF. No account needed.
Multiply the amount by 0.18 to get the GST, then add it to the amount. ₹5,000 at 18% is ₹900 GST, a total of ₹5,900; within a state that is ₹450 CGST + ₹450 SGST.
Divide the total by (1 + rate ÷ 100). For ₹1,180 at 18%: 1,180 ÷ 1.18 = ₹1,000 before GST, so the GST included is ₹180. Choose "Remove GST" in the calculator.
Since 22 September 2025 the main slabs are 5% and 18%, with 40% for selected luxury and sin goods, 0% for nil-rated items, and special rates of 3% and 0.25% for precious metals and rough diamonds. Always confirm the rate for your HSN or SAC code.
Charge CGST + SGST when the supplier and the place of supply are in the same state, and IGST when they are in different states.