How to calculate GST
Adding GST to a price (exclusive → inclusive)
GST amount = Original price × GST rate ÷ 100
Total price = Original price + GST amountExample: ₹10,000 at 18% GST → GST = ₹1,800, total = ₹11,800.
Removing GST from an inclusive price (inclusive → exclusive)
Taxable value = Inclusive price × 100 ÷ (100 + GST rate)
GST amount = Inclusive price − Taxable valueExample: ₹11,800 including 18% GST → taxable value = 11,800 × 100 ÷ 118 = ₹10,000, GST = ₹1,800.
The most common mistake: taking 18% off an inclusive price. 18% of ₹11,800 is ₹2,124, which is wrong. The GST inside ₹11,800 is ₹1,800. Always divide by (100 + rate), which this calculator does automatically.
CGST, SGST and IGST explained
| Type of sale | Taxes charged | Example at 18% |
|---|---|---|
| Within the same state (intra-state) | CGST (to the Centre) + SGST/UTGST (to the state), split equally | 9% CGST + 9% SGST |
| To another state or import (inter-state) | IGST, collected by the Centre | 18% IGST |
The total tax is the same either way. Only the split and who collects it change. The place of supply decides which applies.
GST rates in India (GST 2.0)
From 22 September 2025, the GST Council’s reforms simplified the structure into two main slabs, 5% (merit rate) and 18% (standard rate), plus a special 40% rate for luxury and “sin” goods. Most items that were at 12% moved to 5%, and most at 28% moved to 18%.
| Rate | Typical examples |
|---|---|
| 0% (nil) | Fresh fruit and vegetables, milk, curd, many educational and healthcare services, individual health & life insurance |
| 0.25% / 3% | Rough diamonds / gold, silver and jewellery |
| 5% | Everyday essentials, many packaged foods, most medicines, small hotels, economy transport |
| 18% | Most services (IT, consulting, marketing), electronics, many manufactured goods, restaurants in premium hotels |
| 40% | Tobacco and pan masala, aerated and sugary drinks, luxury cars and large motorcycles |
Rates depend on the exact HSN/SAC code and can change with GST Council notifications. Always confirm the rate for your product on the official CBIC GST rate finder or with your tax professional. The 12% and 28% options are kept for older invoices and transitional cases.