What the withholding formula does with the figures you enter
Withholding is arithmetic rather than judgement. The tax office publishes the coefficients; this page runs them over an amount you type in, and shows every step it took to get there.
What this is. This applies the tax office’s published withholding formulas to figures you type in. It reads no document and stores nothing, it is not tax advice, and it does not work out your position for the year — withholding is an amount collected along the way.
01
The gross figure from one pay period — not the amount that landed in your account, and not a yearly salary.
02
The formulas are written weekly, so a fortnight, a month or a quarter is converted to a weekly figure, run through, and converted back. The monthly conversion has an oddity of its own, and the answer below shows the weekly figure it used.
03
This is the single largest input after the amount itself. If you are not certain which you answered, the figure below is the figure for the option shown, and nothing more.
04
A loan adds a second component on top of the tax, worked out from its own published table rather than from the tax figure.
Stored: nothing
One step here is not marginal. Above $186,050 a year — about $3,577 a week — the study and training loan component is a flat 10% of the whole amount, not 10% of the part above the threshold. It is the one step in these formulas that is not marginal, and treating it as marginal gets the answer wrong for everybody past that line.
This one does not change in the paid tiers. The other free tools stop where documents start. This calculator stops there in every tier: it takes figures a person entered and nothing else, paid or free, and there is no version of it that reads a payslip.