Super Contributions Tax: What to Check Before You Trust the Number

Updated 1 July 2026 · Super and retirement

A Super Contributions Tax Calculator gives a fast answer, but the answer is only as good as what goes in. These are the mistakes we see most often with super contributions tax calculations in Australia, and how to avoid them.

1. Going over the contribution caps

Excess concessional contributions are taxed at your marginal rate, and the cap includes your employer’s contributions.

2. Not checking your employer pays super

Check your fund statements or myGov to confirm contributions arrive. Unpaid super can be reported to the ATO.

3. Leaving multiple accounts open

Each account charges fees and may carry insurance premiums. Consolidating through myGov is usually quick.

4. Ignoring fees

A fee difference of 1% a year looks tiny but can reduce a balance by six figures over a working life.

5. Overlooking the detail that matters most here

After-tax (non-concessional) contributions are not taxed on the way in, because you have already paid tax on that money.

How the tax paid by fund changes with concessional contributions

A common mistake is getting one input slightly wrong. Here is what happens to the tax paid by fund when “Concessional contributions ($)” is off by up to 20% in either direction, with everything else held steady.

Concessional contributions ($)	Tax paid by fund
16,000	$2,400.00
18,000	$2,700.00
20,000	$3,000.00
22,000	$3,300.00
24,000	$3,600.00

At 16,000 the result is $2,400.00; at 24,000 it is $3,600.00. If a small change in this input moves the answer a lot, it is worth double-checking that figure before you rely on the result.

A quick sense check

Concessional contributions are taxed at 15%, or 30% under Division 293 if income plus contributions exceed $250,000. With typical inputs the calculator returns tax paid by fund of $3,000.00. If your own result looks wildly different, check that each figure is in the right unit and period (weekly, monthly or yearly) before drawing conclusions.