GST Calculator
Add or remove Australia's 10% Goods and Services Tax from any amount instantly using the standard ATO divide-by-eleven calculation method for GST.
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How this calculator works
Australian GST is a flat 10% on most goods and services. This tool adds 10% to a GST-exclusive price or extracts the GST component from a GST-inclusive total by dividing by 11.
Adding GST and removing GST are different calculations
Australia's standard GST rate used by this calculator is 10%. To add GST to a GST-exclusive amount, multiply the base amount by 1.10.
To find the GST component inside a GST-inclusive total, you do not simply subtract 10%. The GST portion of a GST-inclusive amount is one eleventh of the total, because the total already represents 110% of the GST-exclusive price.
- Add GST to a GST-exclusive price
- Remove GST from a GST-inclusive price
- See the GST amount and the before/after-GST totals together
Use the GST result for estimates, invoices and quick checks
The calculator is useful for checking quotes, invoices, BAS working figures and everyday business pricing. Whether a particular sale is actually taxable, GST-free or input-taxed depends on the type of supply and your circumstances.
GST registration, input-tax credits, adjustment events and the reporting period can change a BAS liability. This page checks the arithmetic for one entered amount; it does not determine how a transaction must be reported.
Official sources and assumptions
Check the official or authoritative references used to review this calculator's rates, formulas and assumptions.
Frequently asked questions
Why divide by 11?
A GST-inclusive price is 110% of the base price, so the GST portion is one eleventh of the total.
When must I register for GST?
Generally once your turnover reaches $75,000, or $150,000 for not-for-profits.
Is everything subject to GST?
No. Basic food, most health and education services and some other supplies are GST-free.
Content responsibility
Maintained by CalcAussie and last updated 30 September 2026. Checks applied: calculation method, worked examples, Australian terminology, material assumptions, official references where an external rule applies, and user-facing limitations.
Calculator results remain estimates based on the figures entered. Check material decisions against current official information and report a suspected error so it can be reproduced and corrected.
Results are estimates only and are not financial, tax, legal or credit advice.
Rates and thresholds are configured for the 2026–27 Australian financial year and should be reviewed when government settings change.