GST Calculator
Work out GST on an amount, inclusive or exclusive.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
GST Calculator
How to use this tool
- Enter the amount and the GST rate.
- Choose whether the price already includes GST, then press Generate.
- Use Load sample for 1,000 at 18% excluding GST.
Worked example
An amount of 1,000 excluding GST at 18% carries GST of 180.00, for a total of 1,180.00.
What this tool does not do / Limits
This tool is a general arithmetic aid and is not financial advice. It does not check which rate applies to a particular product or place; confirm the correct rate with a tax adviser or the tax authority.
Frequently asked questions
How is GST stripped from an inclusive price?
The base is total divided by (1 + rate), so 1,180 at 18% gives a base of 1,000 and GST of 180.
What if the rate changes?
Enter the rate that applies to your transaction; the tool does not look up rates.
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