GST calculator
Convert GST-inclusive and exclusive prices.
How to read the result
Add GST uses 9% of the pre-tax amount; removing GST uses 9/109 of the inclusive amount. Confirm whether a quoted price already includes GST.
Scope and common mistakes
- Basic 9% conversion only.
- Confirm whether the price includes GST.
- Zero-rated, exempt and rounding cases may differ.
Rules last checked: 4 Sep 2026. See the Sources page.