GST Calculator

When a price is exclusive of GST, the tax is added on top: GST = price multiplied by the rate divided by 100, and the total is the price plus GST. For example, 1,000 rupees at 18 percent gives GST of 180 rupees and a total of 1,180 rupees.

When a price is inclusive, the tax is already inside it, so you work backwards: the net price equals the total multiplied by 100 and divided by 100 plus the rate. A total of 1,180 rupees at 18 percent has a net price of 1,000 rupees and GST of 180 rupees. Note that you do not simply subtract 18 percent of the total, which is a very common mistake.

For a supply within one state, the GST is split equally between the Centre (CGST) and the State or Union Territory (SGST or UTGST), so 18 percent becomes 9 percent CGST plus 9 percent SGST, and 0.25 percent becomes 0.125 percent each. For a supply between states, the full amount is charged as IGST. The calculator shows both views so you can use whichever applies. When the GST amount has an odd paisa, the extra paisa is placed in the second component so the two parts always add up to the total GST.

As checked against official sources on 11 November 2026, India's two main GST rates are 5 percent and 18 percent, with a special 40 percent rate for selected goods and services. Most of the September 2025 reforms took effect on 22 September 2025. The notified goods schedules also include lower rates of 0.25, 1.5 and 3 percent for specified goods, and 12 percent can still apply in specific cases, for example certain brick and tile products under a separate notification. The transitional 28 percent goods schedule for specified tobacco products and pan masala was omitted with effect from 1 February 2026.

The quick choices are 0, 5, 18 and 40 percent, and the Custom field takes any other rate, including fractional rates and 12 or 28 percent where your supply still falls under them. The tool does not decide which rate applies: that depends on the classification of the supply, its effective date and the notification that covers it. Choosing 0 percent simply calculates zero tax. Nil-rated, exempt and zero-rated supplies are treated differently for tax purposes, so the right label for a supply is a question for the notification or a tax professional.

To check a rate, use the official CBIC GST rates page and the CBIC notifications portal, and look up the HSN or SAC code of your item with the HSN/SAC search on the official GST portal. Links to all three are beside the calculator.

Amounts are rounded to the nearest paisa at the end of each calculation. If you add up many invoice lines, your accounting software may round slightly differently and show a difference of a paisa or two.