Your ATO notice and this year's income
All amounts in $. Instalment income is your business income without GST plus interest, dividends and rent, before expenses. It leaves out wages and capital gains. Yellow boxes are waiting for an entry.
Your instalments for each quarter
What you pay each quarter under the ATO rate, the ATO amount, and the variation you entered. The instalment is included in your BAS at label 5A.
Instalment each quarter ($)
What applies to you
Quarterly schedule for 2026-27
When a due date falls on a weekend, you can pay on the next business day.
The effect of varying, and the 85% test
You can vary your rate or amount if you expect this year's tax to be lower. If your varied instalments end up below 85% of what they should have been, the ATO charges interest on the shortfall from each due date.
About this calculator
Purpose. To estimate an Australian resident sole trader's or investor's quarterly PAYG income tax instalments for 2026-27 under the instalment rate and instalment amount methods, the effect of varying them, the interest exposure if a variation is too low, and the balance at year end.
Assumptions and why we chose them. You can change every assumption above. Rates are as at , for the 2026-27 financial year.
- The instalment amount is notional tax on your last assessment, increased by the 5% GDP adjustment for 2026-27, divided by four, unless you enter the amount on your ATO notice. The ATO applies the GDP adjustment to the amount, not to the rate.
- Your expected tax is income tax after the low income tax offset, plus the 2% Medicare levy, on the taxable income you enter, less tax withheld from wages. Study loan repayments and the Medicare levy surcharge are left out.
- The 85% test compares your varied instalments with what the instalments should have been on your actual result. We approximate that as your expected tax, increased by the percentage you enter, spread over the year in line with your instalment income.
- Interest uses the general interest charge rate for , compounding daily, from each instalment due date to the date your income tax is due. The ATO can remit some or all of it.
- The example figures (42,800 of instalment income a quarter, an 8.50% rate and 12,000 of notional tax) follow the ATO style of notice. The expected taxable income of 70,000 shows a year where income has fallen.
Limitations and their effect.
- It covers individuals paying quarterly. Companies, trusts, super funds, monthly payers and the annual or twice-yearly options are not modelled.
- It does not work out your instalment income for you or check that your ATO rate or amount is right. The ATO notice is the authority.
- The interest figure is a guide. The ATO's calculation uses the benchmark on your actual assessment, so the real figure can be higher or lower.
- It does not include study loan repayments, the Medicare levy surcharge, offsets other than the low income tax offset, or credits such as franking credits, all of which change your year-end balance.
- Variations made part way through the year, and the credit at label 5B for earlier quarters, are not modelled. The variation is treated as applying from the first quarter.