Catch-up concessional contribution available.
Maximum concessional contribution this year
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Tax saved vs taking it as salary
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Unused super cap does not have to be lost
Most people think the concessional contributions cap is a strict annual limit: $30,000 of pre-tax money into super for 2025-26, use it or lose it. That is only half right. Since 2018-19 the rules let you carry forward any cap you did not use, for up to five financial years, and roll it into a single bigger contribution later. The catch is a balance test. You can only tap the carried-forward room if your total super balance was under $500,000 at the previous 30 June. This calculator adds your accumulated unused cap to this year's $30,000, checks the balance gate, and shows the tax you would save by contributing the lot.
Why the saving is the gap between two tax rates
A concessional contribution is taxed inside the fund at 15 percent on the way in. If that same money had stayed as salary, it would have been taxed at your marginal rate. So the saving on each dollar contributed is simply your marginal rate, including the Medicare levy, minus 15 percent. The tool applies that spread to the full amount you are able to contribute, which is why a higher earner gets a far larger benefit from the same contribution than someone in a low bracket.
A windfall year with five years of room banked
Take the defaults: $60,000 of unused cap banked over the past five years, a total super balance of $320,000, and a marginal rate of 39 percent including Medicare. Because the balance is under $500,000, the full carry-forward is available. The maximum concessional contribution this year is $30,000 plus $60,000, or $90,000. The tax saved is $90,000 times the 24 percentage-point gap between 39 percent and 15 percent, which is $21,600 kept out of the tax office's hands.
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The chart shows how the $90,000 of pre-tax income is taxed inside super versus as salary. The shaded gap is the saving.
Who this strategy is built for
Carry-forward contributions shine in a year of unusually high income. The classic cases are selling an investment property or shares and facing a large capital gain, receiving a redundancy or bonus, or returning to full-time work after a career break during which you contributed little. Someone who took parental leave for a few years, for instance, will have banked real unused cap and can use it to soak up a later high-income year. The tool is aimed squarely at that planner, the person asking how much they can shovel into super this year and what it is worth in tax.
The mistake that triggers Division 293
Contributing big is not free of consequences at the top end. If your income plus concessional contributions pushes you past $250,000, Division 293 charges an extra 15 percent on the contributions above that line, halving the headline saving on that slice. The contribution is still worthwhile, but the benefit narrows, so very high earners should model Division 293 before assuming the full marginal-rate saving this tool shows. Also remember the contribution must actually land in the fund and be reported before 30 June, and your fund must have your tax file number, or it can be taxed at the top rate.
Common questions
How do I find my unused cap?
The simplest source is your ATO online account through myGov, which tracks your available carry-forward amount year by year. It already accounts for the employer super guarantee and any salary sacrifice you have made, so the figure there is the room genuinely left, not a guess.
Does the employer's 12 percent super count toward the cap?
Yes. The superannuation guarantee your employer pays, currently 12 percent of ordinary earnings, counts as a concessional contribution and uses up part of your $30,000 cap before any voluntary contribution. The tool assumes the figure you enter is room still available after that, so check your ATO record rather than adding on top of the full cap.
What happens to unused cap older than five years?
It expires. The oldest unused amount drops off the rolling five-year window each year, so room you banked six years ago is gone for good. If you have a large balance of old unused cap, there is a quiet deadline pushing you to use it before it lapses.