Calculation Methodology

Calculation Overview

The Salary Sacrifice Calculator compares two scenarios side by side: without salary sacrifice (your current position) and with salary sacrifice (redirecting part of your pre-tax salary into super). Both scenarios run through the same calculation pipeline using official ATO rates for the 2025-26 financial year.

The “without” scenario sets the sacrifice amount to zero. The difference between the two results shows your tax saving, the reduction in take-home pay, and the extra super you accumulate.

Each scenario follows a ten-step pipeline, executed in this order:

1. 1Super Guarantee (SG) — calculated on gross salary at 12%
2. 2Taxable income — gross salary minus the sacrifice amount
3. 3Income tax — applied using progressive tax brackets
4. 4Low Income Tax Offset — reduces tax payable for incomes below $66,667
5. 5Medicare levy — 2% of taxable income (with low-income thresholds)
6. 6Net tax — income tax after LITO plus Medicare levy
7. 7HECS-HELP repayment — calculated on repayment income if a HELP debt exists
8. 8Take-home pay — taxable income minus all taxes and HECS
9. 9Super contributions tax — 15% on total concessional contributions
10. 10Net super added — total contributions minus contributions tax

Every monetary value is rounded to the nearest whole dollar using Math.round(). Display formatting uses Intl.NumberFormat("en-AU") with AUD currency.

Income Tax Brackets

Income tax is calculated using the Australian resident individual tax rates for 2025-26. These incorporate the Stage 3 tax cuts effective from 1 July 2024, which reduced the 32.5% bracket to 30% and lowered the 19% bracket to 16%.

For any given taxable income, the calculator finds the applicable bracket and applies:

For example, on a taxable income of $90,000 the calculator applies the third bracket: $4,288 + ($90,000 − $45,001 + 1) × 0.30 = $17,788.

The first $18,200 is the tax-free threshold. Salary sacrifice reduces your taxable income, which can move you into a lower bracket and reduce the tax payable on each dollar above that threshold.

Low Income Tax Offset (LITO)

The Low Income Tax Offset reduces the amount of tax payable (not taxable income). It is a non-refundable offset — it can reduce your tax to zero but cannot create a refund on its own.

For 2025-26, LITO has three tiers:

The calculator applies LITO after computing the base income tax:

Because salary sacrifice lowers taxable income, it can increase your LITO entitlement — an additional tax benefit beyond the bracket change. For example, reducing taxable income from $70,000 to $65,000 through salary sacrifice restores a $325 LITO that was previously fully phased out.

Medicare Levy

The standard Medicare levy is 2% of taxable income. Low-income earners pay a reduced levy or are fully exempt:

Salary sacrifice reduces taxable income, which directly reduces the Medicare levy. For very low-income earners, a large enough sacrifice could eliminate the levy entirely.

Super Guarantee (SG)

The Super Guarantee is the compulsory contribution your employer makes to your super fund on top of your salary. For 2025-26, the SG rate is 12%.

Key points about SG in the calculator:

• SG is calculated on your gross salary, not on the post-sacrifice amount. Salary sacrifice does not reduce your employer's SG obligation.
• SG counts toward the $30,000 concessional contributions cap. A $100,000 salary generates $12,000 in SG, leaving $18,000 of cap space for salary sacrifice.
• The calculator does not apply the quarterly maximum contribution base ($65,070 per quarter for 2025-26). For most employees this has no effect, but very high earners (>$260,280) may have their SG capped.
• SG is paid by your employer on top of your salary — it does not reduce your take-home pay.

Salary Sacrifice Deduction

Salary sacrifice (also called salary packaging) is an arrangement where your employer redirects part of your pre-tax salary directly into your superannuation fund. This reduces your taxable income by the full amount sacrificed:

This is the core mechanism behind the tax saving. Instead of receiving the sacrificed amount as salary (taxed at your marginal rate of 16% to 45%), it enters your super fund where it is taxed at just 15% as a concessional contribution.

The tax saving per dollar sacrificed depends on the gap between your marginal rate and the 15% contributions tax rate:

Super Contributions Tax

All concessional (before-tax) contributions entering your super fund are taxed at a flat rate of 15%. This applies to both employer SG and salary sacrifice contributions:

For example, if your employer contributes $12,000 SG and you sacrifice $10,000, the total concessional contribution is $22,000. Your super fund deducts $3,300 in contributions tax, and $18,700 is invested in your account.

The 15% rate is significantly lower than most employees' marginal tax rates, which is why salary sacrifice into super produces a tax saving. The trade-off is that these funds are preserved — generally not accessible until you reach preservation age (currently 60).

Concessional Contributions Cap

For 2025-26, the total concessional contributions cap is $30,000 per financial year. This cap covers all before-tax contributions combined:

• Employer Super Guarantee (SG) contributions
• Salary sacrifice contributions
• Personal deductible contributions

The calculator checks your total against the cap:

When total concessional contributions exceed $30,000, the calculator displays a warning. Exceeding the cap has significant consequences:

• Excess contributions are included in your assessable income and taxed at your marginal rate
• A 15% tax offset is applied to avoid double-taxation (since 15% was already paid inside super)
• You can elect to release up to 85% of the excess from your super fund to help pay the additional tax
• The ATO issues an excess contributions determination after you lodge your tax return

HECS-HELP Interaction

A common misconception is that salary sacrifice reduces HECS-HELP repayments. In fact, salary sacrifice has no material effect on HECS repayments. Here's why:

The ATO calculates your compulsory HECS repayment based on your repayment income, which is defined as:

Salary sacrifice is a reportable super contribution, so it gets added back to your taxable income when calculating repayment income:

The sacrifice amount cancels out, leaving your repayment income approximately equal to your gross salary regardless of how much you sacrifice. The calculator reflects this by computing HECS on the full repayment income.

For 2025-26, HECS-HELP uses marginal repayment rates (changed from flat rates in prior years):

Division 293 Tax

Division 293 imposes an additional 15% tax on concessional super contributions for high-income earners. This effectively doubles the contributions tax rate from 15% to 30% for affected individuals.

Your Division 293 income is broadly calculated as:

If your Division 293 income exceeds $250,000:

• Excess = Div 293 Income − $250,000
• Taxable Amount = min(Excess, Concessional Contributions)
• Additional Tax = Taxable Amount × 15%

For example, on a $260,000 salary with $12,000 SG and $10,000 sacrifice: Div 293 income = $248,000 + $22,000 = $270,000. Excess = $20,000, so $20,000 of contributions attract the extra 15% ($3,000 additional tax). The remaining $2,000 is taxed at the standard 15%.

Take-Home Pay Calculation

Take-home pay is the final amount deposited into your bank account after all taxes and obligations are deducted. The calculator assembles it as:

Where:

• Taxable Income = annualSalary − sacrificeAmount
• Total Tax = Net Income Tax + Medicare Levy
• Net Income Tax = max(0, Income Tax − LITO)
• HECS Repayment = compulsory repayment on repayment income (zero if no HELP debt)

The calculator also provides periodic breakdowns:

The effective tax rate shows the proportion of your gross salary that goes to tax:

When comparing scenarios, note that the take-home pay reduction is less than the sacrifice amount. The difference is your tax saving. For example, sacrificing $10,000 on a $100,000 salary reduces take-home pay by approximately $7,000 (because you save roughly $3,000 in income tax and Medicare levy), while the full $10,000 enters your super fund (minus the 15% contributions tax).

Assumptions & Limitations

The following assumptions are built into the calculator. They cannot be changed by the user and are applied consistently across all calculations:

Sources & References

The calculator uses rates, thresholds, and rules from the following authoritative sources: