Calculator
Mortgage Payoff Calculator
Mortgage Payoff Calculator
Interest is charged on your balance minus the offset — the loan itself (and redraw access) stays intact.
Interest Saved
$103,960.43
Payoff Analysis
Paying $2,379.01 in total each month retires the loan in 17 years 2 months instead of 25 — 7.8 years earlier — and saves $103,960.43 in interest. Debt-free arrives around December 2043.
*Modelled on monthly amortisation with your extra repayments and offset balance applied as entered. Actual results vary with lender daily-compounding conventions, fee structures and rate changes. Educational only, not credit advice.
Why Extra Repayments Are Australia's Favourite Investment
Every extra dollar repaid on an Australian home loan earns a guaranteed, tax-free return equal to your interest rate — no asset class offers that combination. At a 6.3% variable rate, an extra repayment 'earns' 6.3% after tax; for a top-bracket earner that matches a term deposit paying around 10%. It is why the humble extra repayment, alongside the offset account, remains the highest-certainty wealth move available to most Australian households. The power comes from permanence and compounding. A regular extra repayment permanently retires future principal years early, so every subsequent month charges interest on a smaller balance — and those savings compound for the remaining life of the loan. On a typical $500,000, 30-year loan, adding $500 a month commonly saves six figures of interest and finishes the debt seven or more years ahead of schedule. The offset account does the same job invisibly: salary and savings parked against the loan cut the interest-bearing balance every day without changing your required repayment, so every spare dollar flows straight to principal automatically. Australian lending adds two refinements worth knowing. Variable loans allow unlimited extra repayments with redraw access — your accelerated payments aren't locked away — while fixed portions usually cap extras at $10,000-$30,000 a year and may charge break costs for early payout. And because required repayments fall only if you ask, keeping payments at the old level after a rate cut is a painless acceleration strategy. This calculator models the whole picture: extra repayments plus offset balance, interest saved versus the minimum-payment path, and the exact debt-free date.
Two Paths, One Balance Sheet
The scheduled repayment is set by the standard amortising formula on your current balance over the remaining term: the payment that exactly retires principal and interest together at term's end. The baseline scenario runs that schedule unchanged — the minimum-payment path — and totals its lifetime interest. Your strategy is then simulated month by month. Each month the balance accrues interest at rate divided by twelve, charged not on the full balance but on the balance net of your offset account — that is precisely how an Australian offset works, reducing the interest-bearing balance daily while leaving the contractual balance untouched. The total payment (scheduled plus extra) then reduces the balance, and because the required payment stays fixed while interest shrinks, an increasing share of each payment attacks principal. The simulation records when the balance hits zero and what interest was charged along the way. The gap between the two paths is your payoff: dollars of interest saved, months or years shaved off the term, and the projected debt-free date. Note the asymmetry the numbers reveal — early extra repayments are worth far more than late ones, because they remove principal from the compounding machine decades sooner. A dollar of extras in year two saves roughly twice what the same dollar saves in year fifteen.
Expert Insights
Early Extras Beat Late Extras by Double
An extra $10,000 paid in year two of a fresh 30-year loan typically saves around double the interest of the same $10,000 paid in year fifteen, simply because it stops ten extra years of compounding on that principal. If you ever debate between accelerating the mortgage and investing, at minimum time your lump sums early — and remember the loan-rate return is guaranteed and tax-free, while most alternatives must beat it after tax just to draw.
The Offset Is Acceleration Without Discipline
Extra repayments require willpower every month; an offset requires one direct-credit form. Salary sweeping through an offset delivers the same interest reduction automatically, keeps the cash fully accessible for emergencies, and preserves redraw capacity on the loan itself. For households whose budgets swing, funding the offset first and sweeping it into a formal extra repayment quarterly gets both discipline and flexibility.
Never Reduce the Required Payment When Rates Fall
When lenders cut rates, most will happily lower your minimum repayment — quietly stretching your loan back toward its original term and restoring the bank's interest. Keeping your repayment at the previous higher level converts every rate cut into pure principal reduction with zero lifestyle change. Borrowers who held their 2021 repayments through the 2022-23 cycle found themselves years ahead even before adding extras.
Actionable Tips
- 1
Start With One Week of Pay a Year
Divide your annual take-home by 52 and add that amount to each month's repayment — roughly 8% extra, invisible in weekly budgeting but transformative over a term. On a $450,000 balance this single habit typically saves $70,000-$100,000 of interest. Automate it as a standing transfer so the decision happens once, not 300 times.
- 2
Check Your Fixed Portion Before Accelerating
Fixed-rate portions usually cap extra repayments (commonly $10,000-$30,000 a year) and charge break costs above them, while variable portions are unlimited. Direct your acceleration at the variable split, and if you're fully fixed, park surplus cash in an offset-linked account until the fixed period expires — then deploy the accumulated lump sum the day it frees up.
- 3
Compare Against Investing Honestly
Extra repayments earn your loan rate, guaranteed and tax-free. Fully franked ASX dividends might outearn that after tax, but with volatility and sequencing risk attached. A reasonable rule: guarantee the win first — build the offset to six months of expenses and clear non-deductible debt above roughly 7% — then let surplus compete between extra repayments and diversified investments based on your risk appetite.
Real-World Examples
The Trans Finished Nine Years Early
On their $460,000 loan, the Tran household added $350 a month — about one week of take-home pay spread thin — and swept bonuses into the offset. The projection showed the loan dying nine years early with $121,000 of interest saved. Twelve years later they made the final repayment at 46, and redirected the entire repayment into their superannuation catch-up contributions the very next payday.
Rebecca's Offset Funded a Career Break
Rebecca built a $60,000 offset against her $540,000 loan instead of making formal extra repayments, saving interest identically while keeping the money liquid. When burnout forced a six-month career break, the offset paid her living costs — then refilled over the following year. The loan never missed a required payment, and she'd earned the loan-rate return on her safety fund the whole way through.
The Okonkwos Held Their Repayment Through the Cycle
When rates fell in 2020-21, the Okonkwos declined the lower minimum repayment on their $520,000 loan. When rates then surged, their budget had already absorbed the higher figure, and the difference had been quietly retiring principal for two years. Their broker calculated the habit alone had put them nearly four years ahead of schedule — before counting a single deliberate extra repayment.
Glossary of Terms
- Extra Repayment
- Any payment above your required minimum that permanently reduces principal, cutting lifetime interest and shortening the loan term.
- Redraw Facility
- Access to extra repayments already made on a variable loan — letting accelerated principal be recovered in emergencies without a new application.
- Offset Account
- A transaction account linked to a variable loan whose balance is subtracted from the loan before daily interest is calculated.
- Debt-Free Date
- The projected month your balance reaches zero under your chosen strategy — the finish line the calculator counts down to.
Frequently Asked Questions
Everything you need to know about this topic.
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.