Salary sacrifice into super 🪺

Employer contributions already use the whole concessional cap, so there’s no room to sacrifice into this year — only carry-forward cap from earlier years could change that.

• The whole trade is a tax arbitrage. Sacrificed dollars skip your marginal rate and cop a flat 15% contributions tax instead. The verdict number is simply what survives into the fund divided by what your take-home actually shrinks by.
• Bracket crossings are handled. The tax saving is computed through the full 2025-26 resident scale (Medicare levy included), not marginal-rate-times-amount — a sacrifice that straddles a bracket boundary saves less than the top rate suggests.
• The $30,000 concessional cap counts your employer’s contributions too. Blow past it and the excess is effectively taxed at your marginal rate, which defeats the purpose. Unused cap from the past five years can be carried forward if your balance is under $500,000 — real, useful, and not modelled here.
• Division 293 can’t be dodged by sacrificing. Above $250,000 of income-plus-contributions, concessional contributions cop an extra 15%. The sacrificed dollars leave your taxable income but re-enter as contributions, so the threshold test doesn’t move. At 30% in the door versus a 47% marginal rate, sacrificing usually still wins — just by less.
• A HELP debt doesn’t shrink either. Reportable super contributions are added straight back into HELP repayment income, so sacrificing changes the repayment by exactly nothing. The 2025-26 marginal system is used: 15% of income over $67,000, stepping to 17% over $125,000.
• Division 293 is assumed released from the fund, which is how most people pay it — so it shows up here as a haircut on what lands in super rather than on your pay.
• Contributions are held flat. No wage growth, no cap indexation, no inflation adjustment — the projection isolates the sacrifice decision rather than forecasting your career. Returns compound at your fund return less fees.
• The catch is preservation. This money is locked away until at least 60. The flip side: in retirement phase, earnings and withdrawals are tax-free — the projected balances here understate the after-tax advantage over investing the same dollars in your own name.
• Not modelled: carry-forward cap, spouse contributions, the government co-contribution, insurance premiums inside super, First Home Super Saver withdrawals, or Division 296 (the proposed tax on balances over $3m).

General information only — not financial advice, and I’m not a financial adviser. Caps, thresholds and rates change most budgets; check anything that matters with someone licensed. Your numbers stay in your browser.