How do I reverse GST in Australia?
Take the GST-included amount and multiply by 1/11 to get the GST part. Then subtract that GST part to get the amount before GST.
Work GST out of a GST-included amount in one step.
Uses the standard GST rate of 10%. Source values reviewed on 21 February 2026.
Uses Australia standard GST rate of 10%.
| Item | Value |
|---|---|
| GST rate | 10% |
| GST part from GST-included amount | GST-included amount x 1/11 |
| Amount before GST | GST-included amount - GST amount |
Take the GST-included amount and multiply by 1/11 to get the GST part. Then subtract that GST part to get the amount before GST.
This reverse GST calculator uses Australia's standard GST rate of 10%.