GST Calculator India: Add or Remove GST (Examples)

Goods and Services Tax (GST) is the single indirect tax that replaced many central and state taxes in India. Whether you run a shop, freelance, or just want to check a bill, knowing how to add or remove GST saves time and prevents mistakes.

GST components: CGST, SGST and IGST

• CGST (Central GST) and SGST (State GST) are charged together on sales within the same state, each at half of the total rate
• IGST (Integrated GST) is charged on sales between different states and on imports, at the full rate
• UTGST applies in union territories without a legislature

For example, an 18 percent GST on an intra-state sale splits into 9 percent CGST and 9 percent SGST. On an inter-state sale the same transaction carries 18 percent IGST.

Common GST rates

GST rates have been revised by the GST Council over the years, and a major rationalisation in September 2025 simplified the structure so that most goods and services now fall into the 5 percent and 18 percent slabs, with a higher rate for a small set of luxury and demerit goods and special rates for items such as gold. Older invoices, and some businesses, still reference the former 12 and 28 percent slabs. Always confirm the current rate for your product or service code (HSN or SAC) on the official GST portal or with your accountant.

How to add GST to a price (exclusive to inclusive)

GST amount = Net price × GST rate ÷ 100. Gross price = Net price + GST amount.

• Net price: 10,000
• GST at 18 percent: 10,000 × 18 ÷ 100 = 1,800
• Gross price: 11,800

How to remove GST from a price (inclusive to exclusive)

When a price already includes GST, divide instead of subtracting the percentage. Net price = Gross price × 100 ÷ (100 + GST rate). A common mistake is subtracting 18 percent of the gross price, which gives the wrong answer.

• Gross price: 11,800 at 18 percent GST
• Net price: 11,800 × 100 ÷ 118 = 10,000
• GST included: 11,800 − 10,000 = 1,800

Tips for accurate GST billing

1. Use the correct HSN code (goods) or SAC code (services) for each item.
2. Mention the supplier and recipient GSTIN on tax invoices where required.
3. Apply CGST plus SGST or IGST based on the place of supply, not just your own location.
4. Keep rounding consistent, and show tax separately on the invoice.
5. Keep records of invoices to claim input tax credit and to file returns on time.

Using a GST calculator

Enter the amount, choose the rate, and pick whether the amount is inclusive or exclusive of GST. The calculator shows the net amount, tax amount and total instantly, which is ideal for quotes, bills and quick checks.

This article is for general information and is not tax advice. Rules and rates change, so verify with official sources or a qualified professional.