How to calculate GST
Adding GST to a price
Final price = Price + GST
Example: ₹1,000 at 18% → GST ₹180 → final price ₹1,180.
Removing GST from an inclusive price
GST = Inclusive price − Price before GST
Example: ₹1,180 including 18% GST → price before GST ₹1,000, GST ₹180.
CGST, SGST and IGST
- Same state (intra-state): GST is split in half. At 18%, that's 9% CGST to the Centre and 9% SGST to the state.
- Different states (inter-state): the full 18% is charged as IGST.
Current GST rates
After the GST rate changes that took effect on 22 September 2025, most goods and services fall under two main slabs: 5% and 18%. A 40% rate applies to luxury and "sin" goods, and some items have special rates, such as 3% on gold. Many essentials are exempt. Always check the current rate for your specific product or service on the official GST portal. Use "Custom" above for any other rate.
Frequently asked questions
Is GST charged on the discounted price?
Yes. If the discount is shown on the invoice at the time of sale, GST is calculated on the price after the discount.
Why do I get a slightly different number on my bill?
Invoices often round each line item, so totals can differ by a rupee or two.
This calculator is for information only. For tax filing, confirm rates and rules with a qualified tax professional.