Two Calculators, One Payslip Story
Every dollar your employer pays you splits into two streams the moment it's calculated: the cash that lands in your bank account after PAYG tax, and the superannuation that's set aside for a retirement decades away. Our PAYG Tax Calculator answers "what do I take home this fortnight?" Our Superannuation Calculator answers "what will that same career add up to at 67?" They're not competing tools — they're two windows onto the same income.
It's easy to treat tax time and retirement planning as separate mental categories — one is a monthly chore, the other feels abstract and far away. But almost every lever you can pull on your payslip today — claiming the tax-free threshold, sacrificing into super, adjusting for a HECS debt — has a direct, calculable effect on both your take-home pay this fortnight and your projected balance at retirement. Understanding the connection is what turns two separate calculators into one coherent financial picture.
This matters most at decision points: negotiating a new salary package, deciding whether a "total remuneration" offer inclusive of super is actually competitive, or working out whether to redirect a pay rise toward lifestyle spending or toward super. Each of those decisions touches both calculators — the PAYG side tells you what you can spend today, the Super side tells you what today's choice is worth at 67. Treating them as one connected story, rather than two unrelated spreadsheets, is what lets you make that trade-off deliberately instead of by accident.
From Gross Salary to Two Different Numbers
Start with a single figure: your gross salary. From there, two calculations run in parallel, not in sequence:
- The PAYG path: your (possibly reduced, if you sacrifice) taxable income has income tax, the Medicare Levy, and any HECS/HELP repayment withheld from it, leaving your net take-home pay.
- The super path: your employer separately pays 12% Super Guarantee on your ordinary time earnings, which is then taxed at a flat 15% inside your fund — a completely different tax treatment to your salary.
How Salary Sacrifice Connects Both Tools
Salary sacrifice is the clearest bridge between the two calculators, because it physically moves a dollar from one path to the other. Every dollar you sacrifice:
- Leaves your PAYG taxable income — lowering your income tax, Medicare Levy, and HECS/HELP repayment for the year (all calculated on the reduced figure).
- Enters your super fund as a concessional contribution — taxed at 15% instead of disappearing at your marginal rate, and immediately starting to compound.
This is exactly why the PAYG calculator has a salary-sacrifice field feeding its taxable income, and the Super calculator has its own salary-sacrifice slider feeding the compounding engine — model the same dollar amount in both, and you'll see the full picture: what it costs you today, and what it's worth to you decades from now.
Marginal Tax Rate: The Bridge Between PAYG and Super
Your marginal tax rate — the rate on your next dollar of income, shown by the PAYG calculator's bracket visualizer — is the single number that determines whether salary sacrifice is worthwhile. The gap between your marginal rate and the flat 15% contributions tax is the entire tax saving.
| Your Marginal Rate (PAYG) | Gap vs 15% Super Contributions Tax | Sacrifice Attractiveness |
|---|---|---|
| 15–16% (second bracket) | 0–1 percentage point | Minimal — barely worth it on tax grounds alone |
| 30% | 15 percentage points | Meaningful — a solid, common case for sacrificing |
| 37% | 22 percentage points | Strong — the gap widens considerably |
| 45% | 30 percentage points | Largest — highest-value bracket for sacrifice |
This is precisely why the Super calculator asks for your marginal tax rate before modelling salary sacrifice — it isn't a generic retirement assumption, it's pulled directly from the PAYG side of your finances.
HECS/HELP and Its Effect on Contribution Decisions
If you carry a HECS/HELP debt, salary sacrifice interacts with it in two directions worth understanding. On the PAYG side, reducing your taxable income can lower your marginal HECS/HELP repayment band for the year — a direct, immediate effect. But "repayment income" for HECS/HELP purposes adds back certain reportable super contributions in some circumstances, meaning the reduction to your compulsory repayment from sacrificing is often smaller than the drop in your headline taxable income would suggest.
Practical takeaway: don't assume salary sacrifice will meaningfully cut your HECS/HELP repayment — model it in the PAYG calculator with your actual numbers rather than relying on a rule of thumb, since the repayment-income add-backs vary by individual circumstance.
Second Job? The Tax-Free Threshold Interacts With Both
Whether you claim the $18,200 tax-free threshold affects your PAYG withholding immediately and obviously. It has a quieter effect on super too: if you're under-withholding on the PAYG side across two jobs and end up with a tax debt at tax time, that's cash you might otherwise have redirected into voluntary super contributions. Getting the tax-free threshold claim right on your main job — and correctly declined on any second job — keeps your cash flow predictable enough to plan super contributions with confidence, rather than being caught out by an unexpected EOFY bill.
A Combined Worked Example
Take a $100,000 salary-plus-super employee in 2026–27, claiming the tax-free threshold, no HECS debt, sacrificing $5,000/yr into super, on a 30% marginal rate:
PAYG Calculator Side
Taxable income drops from $100,000 to $95,000 (after the $5,000 sacrifice). Income tax and Medicare Levy are recalculated on $95,000 instead of $100,000 — a modest but real reduction in withholding, and a smaller net take-home pay than if the $5,000 had been taken as cash, but not a dollar-for-dollar reduction (per the marginal-rate math above).
Super Calculator Side
The same $5,000 sacrifice enters the Super calculator's projection as a concessional contribution, taxed at 15% ($750) instead of the person's 30% marginal rate. Net $4,250 is added to the fund and begins compounding immediately, on top of the $12,000 annual employer SG contribution (also taxed at 15% in the fund). Run forward to age 67, that single ongoing $5,000/yr habit — modelled with the Super calculator's monthly-step compounding — becomes a meaningfully larger slice of a multi-hundred-thousand-dollar addition to the final balance.
Try it yourself: put $5,000 into the PAYG calculator's salary sacrifice field first, note the change in your net pay, then enter the same $5,000/yr into the Super calculator's salary sacrifice slider to see where that trade-off ends up decades later.
When to Use Which Calculator
| Question You're Asking | Use This Calculator |
|---|---|
| "What will land in my bank account this fortnight?" | PAYG Tax Calculator |
| "Should I claim the tax-free threshold on my second job?" | PAYG Tax Calculator |
| "How much HECS/HELP will be withheld this year?" | PAYG Tax Calculator |
| "What will my super balance be at retirement?" | Superannuation Calculator |
| "Is salary sacrifice worth it for me long-term?" | Both — PAYG for the cost today, Super for the payoff later |
| "Am I at risk of exceeding my concessional cap?" | Superannuation Calculator |
As a rule of thumb: reach for the PAYG calculator whenever a decision changes what lands in your account in the next few weeks, and reach for the Super calculator whenever a decision changes what you'll have access to in the next few decades. Salary sacrifice is the one input that genuinely belongs in both, since it's the single lever that moves money between the two time horizons in one action.
Frequently Asked Questions
Do I need to use both calculators every time?
No — most people only need the PAYG calculator for everyday payslip questions. The Super calculator is worth revisiting whenever your salary changes materially, you're considering salary sacrifice, or roughly once a year as part of a broader financial check-in.
If I increase my salary sacrifice, do I need to update both tools?
Yes — enter the new amount in the PAYG calculator to see the updated take-home pay impact, and in the Super calculator to see the updated long-term projection. They don't share data automatically; each is a standalone model.
Which number is more important — my take-home pay or my projected super balance?
Neither is inherently more important — they serve different time horizons. Take-home pay determines your day-to-day budget and lifestyle; your super balance determines your retirement standard of living. Most sound financial plans balance both rather than optimising one at the total expense of the other.
This article is for general educational purposes only and is not tax, financial, or retirement advice. Figures reflect currently legislated and ATO-indexed rates as at July 2026 and may be updated by future budgets or indexation. Always confirm your specific circumstances with the ATO, your super fund, or a licensed financial adviser.
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