This article provides general information only and does not constitute personal financial advice. It has been prepared without taking into account your objectives, financial situation or needs. Before acting on any information in this article, you should consider whether it is appropriate for you and seek advice from a licensed financial adviser if necessary.

December 31 represents the final opportunity each year to set up or adjust salary sacrifice arrangements that will apply to the coming year. While Australia’s financial year runs from July 1 to June 30 (and that is when concessional contribution caps are measured), the calendar year-end carries practical significance for superannuation planning. Many employers process final payroll changes before the Christmas shutdown, and December offers a natural checkpoint to review your contributions strategy well ahead of the June 30 rush.

What Is Salary Sacrificing Into Super?

Salary sacrificing (also called salary packaging) into superannuation means arranging with your employer to direct part of your pre-tax salary straight into your super fund. Instead of receiving that portion as take-home pay (taxed at your marginal rate, which can be as high as 45% plus the 2% Medicare levy), the contribution is taxed at just 15% inside your super fund.

For someone on a marginal tax rate of 37%, the difference is substantial. A $5,000 salary sacrifice contribution costs you $4,250 in after-tax income (15% tax inside super), compared to receiving $3,150 after tax at the 37% marginal rate. That $1,100 difference stays invested in your super, compounding over time.

The Concessional Contribution Cap

Salary sacrifice contributions are classified as concessional contributions, the same category as your employer’s Superannuation Guarantee (SG) payments. According to the Australian Taxation Office, the concessional contributions cap for the 2026-27 financial year is $30,000 (ATO, 2026).

This cap covers all concessional contributions across the financial year (July 1 to June 30), including employer SG, salary sacrifice, and any personal deductible contributions you claim. Exceed the cap and you will pay additional tax on the excess amount at your marginal rate, minus a 15% offset.

Why December 31 Matters

Although the contribution cap is measured over the financial year, the calendar year-end is significant for several practical reasons:

Employer payroll cycles: Many organisations close their payroll systems for changes in mid to late December. If you want to commence or adjust a salary sacrifice arrangement to take effect from January 1, you typically need to submit the paperwork in early to mid-December.

Year-end review: December provides a natural opportunity to check your year-to-date concessional contributions (your employer’s SG plus any salary sacrifice already made from July to December). Your payslip or super fund statement will show contributions received. If you are well below the $30,000 cap, you might choose to increase your salary sacrifice rate for the second half of the financial year. If you are close to the cap, you can reduce or pause contributions to avoid breaching it.

Avoiding the June rush: Waiting until May or June to organise super contributions often means competing with everyone else doing year-end tax planning. Payroll teams are busier, and there is less margin for error if contributions need to be received by June 30 to count in the current financial year. Planning in December spreads the load and gives you more control.

Read also: How to Maximise Your Superannuation Contributions Before 30 June in Australia

Catch-up contributions: If your total super balance was below $500,000 on the previous June 30, you can carry forward unused concessional cap amounts from the past five financial years. Reviewing your position in December lets you determine whether you have unused cap to utilise before the financial year ends.

How to Arrange Salary Sacrifice Before Year-End

Contact your employer’s payroll or human resources team by early December. Most employers will require you to complete a salary sacrifice agreement form, specifying the amount (either a dollar figure per pay period or a percentage of your salary) and confirming which super fund should receive the contributions.

Check your current year-to-date concessional contributions by reviewing your payslips and logging into your super fund account. Add up employer SG contributions already made since July 1, then calculate how much cap room remains. As foundational texts such as Principles of Finance explain, tax-effective contribution strategies rely on understanding annual limits and timing.

Ensure your super fund details are correct and up to date. Contributions sent to the wrong fund or using incorrect member details can be delayed, potentially causing them to fall into the wrong financial year for cap purposes.

Key Considerations

Salary sacrificing reduces your take-home pay. Make sure you can afford the reduction and that you are still meeting your day-to-day expenses and any debt commitments.

Super is preserved until you reach your preservation age (currently between 60 and 65, depending on your birthdate) and meet a condition of release, such as retirement. Money salary sacrificed into super is locked away until then, so do not sacrifice funds you will need in the short term.

If you earn more than $250,000 per year, an additional 15% Division 293 tax applies to concessional super contributions, effectively bringing the tax rate on those contributions to 30%. High earners should factor this into their planning.

According to ASIC MoneySmart, all Australians should periodically review their super contributions to ensure they are on track for retirement (MoneySmart, 2026). December is an ideal time for that check, well ahead of the financial year-end deadline.

Final Thought

Salary sacrificing into super before December 31 is less about a hard deadline and more about smart timing. It gives you a head start on the financial year, ensures your arrangement is in place before the holiday shutdown, and positions you to make the most of your concessional contribution cap without the stress of a last-minute scramble in June. If you have cap room available and your budget allows, acting before year-end can deliver meaningful long-term benefits for your retirement savings. For personalised advice on how much to contribute and whether salary sacrificing suits your circumstances, consult a licensed financial adviser.