Calculator
Offset Account Savings Calculator
Offset Account Savings Calculator
Includes the 2% Medicare Levy — e.g. 32% for incomes between $45,001 and $135,000.
Interest Saved Over Remaining Term
$152,517.79
Offset Analysis
Every dollar in your offset saves $255.83 of interest this month — about $3,070 across year one and $152,517.79 over the remaining term if the balance holds and repayments stay unchanged. Because offset savings arrive as avoided loan interest, they are not taxable income; a savings account would need 9.03% before tax at your 32% marginal rate to beat it.
*Assumes the offset balance stays constant and minimum repayments are unchanged. Offset accounts are generally offered on variable-rate loans only, and features vary by lender. Educational only, not financial advice.
The Tax-Free Return Hiding in Your Mortgage
An offset account is a transaction account linked to your home loan: every dollar sitting in it is subtracted from your loan balance before the bank calculates interest, even though it stays fully yours — spendable, transferable and available whenever you need it. On a $600,000 loan with $60,000 parked in offset, interest is charged on $540,000 instead. That saving compounds for as long as the money stays put, which is why an offset is one of the most powerful cash management tools Australian mortgage holders have. The feature that makes offsets remarkable is tax treatment. Interest you earn in a savings account is taxable income at your marginal rate — up to 47% including the Medicare Levy. Interest you avoid through an offset was never income at all, so there is nothing to declare and no tax to pay. For a middle-income earner, a savings account paying 4.75% delivers roughly what an offset achieves against a similar loan rate without any tax drag. That gap widens further for high earners, which is why offsets are a fixture of Australian wealth-building strategy — right alongside extra repayments and redraw facilities, each with different trade-offs around flexibility and future borrowing.
Interest Avoided, Month by Month
The core arithmetic is simple: monthly interest saved equals your offset balance multiplied by the loan's monthly rate (annual rate divided by twelve). A $50,000 offset against a 6.14% loan saves about $256 in the first month alone — roughly $3,070 across year one if the balance holds. The calculator then runs two full amortisation schedules side by side: one starting from your full loan balance, and one starting from the balance minus the offset. Because both use the same minimum repayment, the offset version pays principal faster, so the saving compounds and the loan finishes early. The comparison metric matters most: to match the offset's benefit after tax, a savings account must pay your loan rate grossed-up by your marginal rate — loan rate divided by (one minus your tax rate). At a 6.14% loan rate and a 32% marginal rate that is about 9.03% before tax, a yield no deposit account pays. Two caveats keep the maths honest: the simulation assumes your offset balance never dips, and offsets usually attach to variable-rate loans that carry slightly higher rates than basic products — typically a 0.1–0.2% premium worth checking before choosing between an offset and a plain discount loan.
Expert Insights
Offset Versus Extra Repayments Is About Flexibility
Both strategies save the same interest per dollar while the money stays applied. The difference is reversibility: extra repayments are the bank's money once made, and getting them back means applying for a redraw, which can take days and may carry fees or conditions. An offset balance remains yours instantly. If the money is your emergency fund or a future deposit, the offset wins despite its marginally higher loan rate; if it is surplus cash you will never need back, extra repayments on the cheapest available loan often edge ahead.
Redraw Is Not Offset — Especially for Investors
A redraw facility also reduces the interest charged, but money paid into redraw is treated as a repayment of the loan itself. Redrawing later re-borrows that amount and, for investment property loans, contaminates the deductibility of the redrawn portion — the ATO traces funds to their purpose. An offset keeps your cash legally separate from the loan, preserving clean records. Property investors who might ever convert a home to a rental should treat the distinction as structural, not cosmetic.
Salary Domicile Turns the Offset Into a Daily Machine
Because offset interest is calculated daily on the net balance, having your salary deposited into the offset from payday compresses the average balance less than you would think — the money starts working the day it lands. Households that route all income and spending through one offset-linked account capture the maximum day-count benefit automatically. Pair it with a credit card paid in full inside the interest-free window and your money spends up to fifty-five days working in the offset before the bills settle.
Actionable Tips
- 1
Park Your Emergency Fund in the Offset
An emergency fund's job is to be boring and reachable. Inside an offset it earns your full loan rate tax-free instead of a taxable deposit rate, yet stays instantly accessible via card or transfer. A household holding a $30,000 buffer in offset rather than a 4.75% savings account at a 32% marginal rate comes out roughly $700 a year ahead on a 6% loan — with zero additional risk taken.
- 2
Check Whether the Offset Package Pays Its Way
Offset accounts usually arrive bundled with an annual package fee — commonly $300–$395 — attached to a slightly higher variable rate than no-frills products. Run the numbers both ways: multiply the fee plus the rate difference by your balance, and compare that cost against the interest saved. Balances above roughly $20,000–$30,000 usually justify the package; below that, a basic variable loan with no offset but a lower headline rate frequently wins.
- 3
Split Large Windfalls Across Goals
If you hold $200,000 and plan to buy an investment property in three years, keeping it all in offset maximises today's saving but quietly converts it into home-loan equity, not accessible cash discipline. Decide explicitly how much is emergency buffer, how much is the future deposit, and whether the deposit portion should sit in offset (guaranteed return) or a term deposit ladder (known maturity dates). Running this calculator with different offset balances prices each choice.
Real-World Examples
The Kellys Turned Their Savings Account Into a Loan Killer
Sarah and Tom Kelly kept $80,000 of house-deposit leftovers in a bonus saver earning 4.75% while carrying a $650,000 mortgage at 6.14%. Moving it into offset saved them about $490 a month in interest — more than double their after-tax savings interest — and, with repayments unchanged, cut roughly four years off their 25-year term. Nothing about their spending changed; the same dollars simply stopped being taxed on the way in.
Priya Priced the Package Fee Before Signing
Priya's lender quoted a Professional Package: $395 a year and a rate 0.15% above their basic variable. With just $25,000 likely to sit in offset, the calculator showed first-year interest saved near $1,530 — but the fee plus the rate premium consumed almost half of it. She took the basic loan and kept her savings in a term deposit ladder instead, revisiting the maths whenever her balance crossed $40,000.
David Protected His Future Deductions
David planned to rent out his apartment in five years and buy a house in the meantime. His broker warned him that paying $100,000 into the investment loan and redrawing it for the new home would taint his interest deductions forever. Instead he kept the $100,000 in an offset against the investment loan: identical interest saving today, and when the property converts to a rental, the full original loan balance — and therefore the full deduction — remains intact.
Glossary of Terms
- Offset Account
- A savings or transaction account linked to a home loan whose balance is deducted from the loan balance before daily interest is calculated. Money stays fully accessible, and the interest avoided is not taxable income.
- Redraw Facility
- A feature letting you withdraw extra repayments already made on a loan. It saves interest like an offset, but withdrawn amounts re-borrow the debt and can affect tax deductibility on investment loans.
- Taxable-Equivalent Rate
- The pre-tax interest rate a savings product must pay to match a tax-free benefit such as an offset. Calculated as the offset's loan rate divided by one minus your marginal tax rate.
Frequently Asked Questions
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Ivy Sinclair-Wren
Financial Chaos Analyst
Ivy Sinclair-Wren is a Financial Chaos Analyst covering investing, AI, wealth psychology, and the emotional consequences of opening finance apps during market crashes. Based in Melbourne, she specializes in demystifying the Australian tax code and helping users navigate the intersection of spreadsheet logic and human irrationality.