How to use the GST calculator
Enter an amount, pick the GST rate and say whether the amount is before GST or already includes it. The calculator shows the GST and how it splits between the centre and the state.
For example, a ₹10,000 service at 18% GST carries ₹1,800 of tax: ₹900 CGST and ₹900 SGST within the same state, or ₹1,800 IGST if the buyer is in another state. The invoice total is ₹11,800.
GST formulas
Add GST: GST = amount × rate ÷ 100Remove GST: price before GST = amount × 100 ÷ (100 + rate)
To find the GST inside ₹11,800 at 18%: 11,800 × 100 ÷ 118 = ₹10,000, so GST is ₹1,800.
Current GST slabs
From 22 September 2025, the GST Council replaced the 12% and 28% slabs with a simpler structure.
| Rate | Applies to (examples) |
|---|---|
| 0% | Fresh food, milk, health and life insurance for individuals, many essentials |
| 5% | Packaged food, most medicines, daily-use items, many services |
| 18% | Most goods and services, including electronics, cars up to set limits, telecom and financial services |
| 40% | Luxury and sin goods such as tobacco, pan masala, aerated drinks and large cars |
| 3% | Gold, silver and jewellery |
| 0.25% | Rough diamonds and precious stones |
Check the exact rate for your product or service code (HSN or SAC) on the GST portal before billing.
Frequently asked questions
How do I add GST to a price?
GST amount = price × GST rate ÷ 100. Final price = price + GST amount. For ₹1,000 at 18%, GST is ₹180 and the final price is ₹1,180.
How do I remove GST from an inclusive price?
Price before GST = inclusive price × 100 ÷ (100 + GST rate). For ₹1,180 including 18% GST, the price before GST is ₹1,000 and GST is ₹180.
What are the current GST slabs?
Since 22 September 2025 most goods and services are taxed at 5% or 18%, with a 40% rate on luxury and sin goods. Special rates of 3% (gold and silver) and 0.25% (rough diamonds) continue, and many essentials are exempt.
What is the difference between CGST, SGST and IGST?
For a sale within the same state, GST is split equally between the centre (CGST) and the state (SGST). For a sale to another state, the whole amount is charged as IGST.
Last reviewed: 13-10-2026. Rates and rules are checked against official sources; tell us if something has changed. Contact