GST Calculator
Add or remove GST and calculate the tax amount.
What is GST Calculator?
This free online tool helps you work with GST quickly and without signup. It is designed for simple everyday use on desktop and mobile browsers.
How to use this calculator
Enter the values you already know, choose any relevant rate or mode, then calculate. The result is shown immediately so you can test different scenarios without creating an account.
Practical tip
For business decisions, keep the original inputs with your result. Rates, taxes, fees and costs can change, so use the calculator as a planning aid and confirm any official amount with the relevant provider or authority.
Why use this tool?
- Free to use with no account required.
- Clear inputs and immediate results.
- Mobile-friendly interface.
- Related tools are linked below for the next step in your workflow.
Adding GST to a price
To add GST, multiply the pre-tax amount by the GST rate and add the result to the original amount. At a 10% rate, a 250 pre-tax amount has 25 GST and a 275 tax-inclusive total.
Removing GST from an inclusive amount
To find the pre-tax amount from a GST-inclusive total, divide by 1 plus the GST rate as a decimal. This reverses the original tax addition accurately.
Use the rate required for your location
GST systems differ between countries, and some goods or services can be zero-rated, exempt or subject to special rules. ToolViso calculates the numbers you enter; it does not determine tax liability.
Frequently Asked Questions
Is GST Calculator free to use?
Yes. The tool is available without signup or a paid account.
Does this tool work on mobile devices?
Yes. The interface is responsive and is designed to work in modern mobile and desktop browsers.
Can I use the result for official or financial decisions?
Use the result as a practical estimate. Confirm legally, financially or operationally important figures with the relevant official source, provider or professional.
How do I calculate GST from a tax-exclusive amount?
Multiply the tax-exclusive amount by the GST rate, then add the GST amount to get the total.
How do I extract GST from an inclusive price?
Divide the inclusive price by 1 plus the GST rate as a decimal to find the pre-tax amount.