Skip to main content

COVID-19 Alert Level 1 If you've been affected by COVID-19, we may be able to help. Find out more


We work out your ratio percentage

Contact us to request a ratio percentage.

We'll divide your residual income tax (RIT) for the last tax year by your total GST-taxable supplies for the same year.

If last year's figures aren't available, we'll use the residual income tax and total GST-taxable figures from the previous year.

We'll decide your ratio percentage

We'll let you know what it is before your first provisional tax payment due date.

Work out your provisional tax for the year

Multiply the ratio percentage by your GST-taxable supplies for the previous 2 months.

File your return and make payment

You’ll make your provisional tax payments along with your GST returns. You can make payment or request a ratio percentage in myIR.

myIR Secure Online Services