Compute Super contribution tax impact.
Tax saved this year
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15% contributions tax
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Employer SG (12%)
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Why super is the most tax-effective dollar you can move
The logic of putting extra money into super is simple arbitrage between two tax rates. Money you earn as salary is taxed at your marginal rate, which for most working Australians is 30 percent or more. Money you direct into super as a concessional contribution is taxed at just 15 percent on the way in. The gap between those two numbers is your saving, repeated every year you do it, on top of decades of compounding inside a low-tax environment. This calculator quantifies that gap: you enter your salary, the concessional contribution you plan to make, and your marginal rate, and it shows the net tax saved, the 15 percent contributions tax, and the employer super guarantee.
The $30,000 cap and what counts inside it
Concessional contributions are capped at $30,000 for 2026-27, and this is a hard ceiling that catches everything pre-tax: your employer's 12 percent super guarantee, any salary sacrifice you arrange, and any personal contributions you later claim as a tax deduction. The cap is not on top of your employer contributions; it includes them. On a $100,000 salary the guarantee alone is $12,000, which already eats into the $30,000, leaving about $18,000 of room before you breach the cap. Go over and the excess is effectively taxed at your marginal rate plus an interest charge, so the cap is a number worth tracking carefully across all your contribution sources.
A $15,000 contribution on a 32 percent rate
Take a $100,000 salary, a $15,000 concessional contribution, and a 32 percent marginal rate. The tool shows tax saved this year of $2,550, a 15 percent contributions tax of $2,250, and an employer super guarantee of $12,000. The working is below.
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That $2,550 is a one-year saving, and it repeats annually. The higher your marginal rate, the wider the 15 percent gap and the bigger the saving, which is why salary sacrifice is most powerful for those on the 37 and 45 percent rates.
The trade-off and a high-income wrinkle
The catch with all of this is access. Every dollar you push into super is locked away until you reach your preservation age, currently 60 for anyone retiring now, so the tax saving comes at the cost of liquidity for years or decades. That is the right trade for long-term retirement money, but a poor one for a house deposit you need in three years, so do not sacrifice so hard that you starve your short-term savings. A useful tip is the carry-forward rule: if your total super balance is under $500,000, you can use unused concessional cap from the previous five years, which lets someone with a one-off high-income year or a capital gain make a much larger deductible contribution to soak up the tax.
High earners face an extra layer called Division 293. If your income plus your concessional contributions exceeds $250,000, the contributions tax on the amount above that line doubles from 15 to 30 percent. The saving is still real, because 30 percent inside super beats the 47 percent top marginal rate outside it, but it is smaller than this tool's simple 15 percent assumption suggests. The calculator uses the standard 15 percent rate, so if your income is near or above $250,000, treat the saving shown here as the optimistic end and expect a slightly smaller benefit once Division 293 applies.
Is salary sacrifice the same as a personal deductible contribution?
They reach the same place by different routes. Salary sacrifice is arranged through your employer, who pays the money into super before you ever see it, so your taxable salary is reduced at the source. A personal deductible contribution is money you pay in yourself from your after-tax account, then claim back as a deduction in your tax return. Both are concessional and both count toward the $30,000 cap, so choose whichever is administratively easier for you.
What happens if I accidentally exceed the concessional cap?
The excess is added back to your assessable income and taxed at your marginal rate, with an offset for the 15 percent already paid inside super, plus an interest-style charge for the timing. You can elect to withdraw up to 85 percent of the excess to help pay the bill. It is not a disaster, but it removes the benefit, which is why tracking all your contribution sources against the single $30,000 cap matters.