How salary sacrifice super contributions affect your gross pay and tax

What is a salary sacrifice super contribution?

A salary sacrifice super contribution is a voluntary arrangement where you and your employer agree to reduce your pre-tax salary in exchange for the employer making extra superannuation payments into your fund. This is different from the compulsory super guarantee (SG), which from 1 July 2026 is 12% of your ordinary time earnings. With salary sacrifice, you choose to forego some cash now to boost your retirement savings.

The key benefit is tax. The sacrificed amount is not included in your assessable income, so you pay less income tax and Medicare levy. Inside your super fund, the contribution is taxed at only 15% (up to the concessional cap), which is often lower than your marginal rate. However, your take-home pay drops because you are receiving less cash each pay period.

How does salary sacrifice affect your gross pay and the Salary Index?

The Salary Index measures full-time adult ordinary-time earnings before any deductions. The national line is 100, which equals $108,352 per year (based on ABS Average Weekly Earnings, May 2026). When you salary sacrifice, your gross pay as reported to the ATO is lower, but the index benchmark is based on what you would earn without the sacrifice. So if your pre-sacrifice salary is $80,000, your index is 73.8 (80,000 ÷ 108,352 × 100). That figure does not change because you sacrifice – the index uses the ordinary-time earnings before any salary packaging.

If you compare your post-sacrifice taxable income to the index, you would get a lower number, but that is not the correct comparison. The index is a benchmark for gross ordinary-time earnings, not for taxable income. Always use your full salary before sacrifice when checking where you sit against the national line.

Tax and super implications

Salary sacrifice super contributions count towards your concessional contributions cap. For 2026–27, the cap is $30,000 (check the ATO for updates). Contributions above the cap are taxed at your marginal rate plus an excess concessional contributions charge. The super guarantee also counts towards this cap, so you need to coordinate both.

Because the sacrificed amount is taxed at 15% inside super rather than at your marginal rate (which could be 30%, 37%, or 45% plus 2% Medicare), you save tax. But the money is locked away until you meet a condition of release (usually retirement after age 60).

Example with national minimum wage context

The national minimum wage from 1 July 2026 is $26.44 per hour, or $52,255 per year (index 48.2). If you earn at that level, salary sacrifice is less common because you need the cash now. But if you earn above the tax-free threshold, the savings start to matter.

Consider someone earning $100,000 per year (index 92.3). They decide to salary sacrifice $15,000 to super. Their taxable income becomes $85,000. Tax on $85,000: $0 on first $18,200, 15% on $26,800 ($4,020), 30% on $40,000 ($12,000) – total $16,020. Plus Medicare 2% ($1,700) = $17,720. Take-home pay is $85,000 – $17,720 = $67,280. Without sacrifice, tax on $100,000: $0 on $18,200, 15% on $26,800 ($4,020), 30% on $55,000 ($16,500) – total $20,520. Medicare $2,000 = $22,520. Take-home $77,480. So sacrifice reduces take-home by $10,200 but adds $15,000 to super (plus the 12% SG on the original $100,000). The net benefit depends on how long the super grows.

State and industry context

Your gross pay relative to the index varies by state and industry. For example, Western Australia has an index of 106.9 (annualised $115,825), while Tasmania is 88.6 ($96,008). If you work in a high-index state, your pre-sacrifice salary is likely higher, making salary sacrifice more attractive because you are in a higher tax bracket. Similarly, industries like mining (index 154.7) and professional services (114.7) have higher average earnings, while retail (75.9) and accommodation (72.5) are lower. Salary sacrifice can help high earners reduce tax, but low earners may not benefit as much.

Important caveats

Salary sacrifice must be agreed in writing before you earn the income. It cannot reduce your pay below the relevant award rate or the national minimum wage. Also, it affects government benefits such as Family Tax Benefit, Child Care Subsidy, and the Medicare Levy Surcharge. The pay guides and how the index works pages provide more detail on how gross earnings are measured.

Remember that the Salary Index is a benchmark for full-time adult ordinary-time earnings before any salary packaging. Your personal index is calculated from your gross salary before sacrifice. If you want to see how your total remuneration (including super) compares, you can add the SG and sacrifice to your gross, but the index itself remains a gross ordinary-time measure.

Summary

Salary sacrifice super contributions are a tax-effective way to boost your retirement savings by reducing your taxable income. They lower your take-home pay but increase your super balance. When comparing your pay to the national index, always use your pre-sacrifice gross salary. The index line of 100 ($108,352) is a useful reference point, but your personal financial situation depends on your tax bracket, super caps, and long-term goals.