GST Calculator

How the GST calculator works

GST, or goods and services tax, is a value-added tax charged on most sales in countries such as Australia, India, Canada, New Zealand and Singapore. The calculator works in two directions. Choose “Add GST” when you know the price before tax (the net price) and want the total a customer pays. Choose “Remove GST” when you have a GST-inclusive total, for example a receipt, and want to split it into the net price and the tax.

Pick a rate from the dropdown or choose Custom and type your own. The results show the net price, the GST amount and the gross price, plus the share of the gross price that is tax.

The formulas

When you remove GST, do not just subtract the rate from the total. Taking a percentage off the gross price gives the wrong answer because the tax was calculated on the smaller net figure.

Example: At 10%, a net price of $1,000.00 has GST of $100.00, so the gross price is $1,100.00. The GST is 9.09% of that gross price, which is why you divide by one plus the rate when working backwards. These numbers are an illustration, not a quote for any real sale.

Typical uses include quoting a customer the GST-inclusive price, checking how much GST is on a supplier invoice so you can claim it where your rules allow, and splitting a receipt into its net and tax parts for bookkeeping. Rounding rules differ between tax authorities, so a figure on an official invoice can differ by a cent from the result shown here.

Rates in the dropdown

GST rates are set by governments and they change. Check the current rate with the tax authority before you invoice. At the time of writing (November 2026) the rates below match these official sources:

• Australia: 10 percent on most goods and services, per the Australian Taxation Office.
• India: the GST Council moved the main structure to 5 percent and 18 percent, with 40 percent on a few select goods and services, from 22 September 2025, replacing the 12 and 28 percent slabs. See the Press Information Bureau release. The old 12 and 28 percent options are kept only for checking older invoices. Some goods are taxed at nil or other rates, so confirm your item.
• Canada: 5 percent federal GST, per the Canada Revenue Agency. Some provinces charge HST instead, such as 13 percent in Ontario and 14 percent in Nova Scotia, so use the Custom rate for those.
• New Zealand: 15 percent, per Inland Revenue.
• Singapore: 9 percent, per IRAS.

Zero-rated, exempt and special-case items are not handled here. This calculator is for general information and is not tax advice. For US-style sales tax, use our guide to how to calculate sales tax.

Frequently asked questions

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