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Our research starts with a practical pay question, uses published Australian rules and shows the calculations. These are modelled comparisons, with the assumptions and data available for readers to check.
What does a four-day week cost after tax?
Reducing five equal-length days to four cuts gross salary by 20%. At a $100,000 starting salary, our no-HELP, no-hospital-cover example retains 82.5% of take-home pay. The cost is $1,133 a month.
The Four-Day Week Pay Index compares nine starting salaries and four HELP and hospital-cover settings. It shows why multiplying net pay by 80% can misstate the cash cost.
How much of a $10,000 pay rise do you keep?
For a move from $100,000 to $110,000 without HELP or qualifying hospital cover, our example keeps $5,710 of the $10,000 increase. With hospital cover, the cash gain is $6,800, before allowing for the insurance premium.
The pay-rise study compares thirteen starting salaries and shows how repayment and surcharge thresholds can change the gain. Each row is a full-year comparison under the same assumptions.
One income or two at the same household salary?
The same household gross pay can produce different after-tax cash when it is genuinely earned by one person or shared across two earners. Our study works through a $100,000 example and compares six household salary totals.
All 16 scenarios show individual tax components. Benefits, childcare, extra working hours and other household costs are outside this tax comparison.
How to use and cite the work
Each report links to its calculation rows in CSV and its complete methods and sources in JSON. Please cite Paycalcmate, the report title, financial year and report link when discussing an example. Keep the scenario description attached to a number.
Our calculations are separate from ABS survey findings. Salary guides identify the original statistical source, its population and its measurement date. A new calculation date does not make an older earnings survey a new one.
Sources you can check
Sources checked for this page on 2 October 2026. Statistics keep their own measurement dates.