Calculator
Debt Payoff Calculator
Debt Payoff Calculator
Cash in an offset account or redraw reduces the balance charged interest — the tax-free equivalent of earning your loan rate.
Debt-Free Timeline
2 yr 11 mo
Payoff Analysis
With the scheduled repayment of $615.79 a month plus $300 extra and $5,000 held in offset, the $28,000 debt is gone in 2 yr 11 mo at a cost of $3,437.87 in interest. That is $5,509.71 of interest and 2 yr 1 mo of payments wiped out compared with the plain 5 yr schedule. The offset balance alone accounts for $1,855.88 of the saving — money that earns you loan-rate interest with zero tax on the benefit.
*Assumes a fixed rate, fixed scheduled repayment set by the term you enter, and no new borrowing. Offset savings assume the balance stays constant. Educational only — not credit advice.
Knowing When the Debt Actually Ends
Most Australians with a personal loan, car loan, or card balance know the repayment amount but have never properly calculated the finish line: how many months, how much total interest, and what happens if they pay a little more each month. Lenders are not incentivised to make that visible — a loan serviced at its scheduled minimum is a loan that pays interest for its full contracted life. For the borrower, the gap between the scheduled path and an accelerated one is often thousands of dollars and years of payments. This tool maps both paths for any single debt. Enter the balance, the rate, and the remaining term to see the baseline: the scheduled repayment, the months to clear, and the total interest you are contracted to pay. Then add two accelerators that are particularly relevant in Australia. One is extra repayments — a fixed additional amount each month, which chips directly at principal and compounds into shrinking interest charges. The other is an offset buffer: cash held in a linked offset account (common on some personal and investment loan products) that reduces the balance charged interest dollar-for-dollar. Because the tax-free benefit of offset equals your loan rate, it is frequently the best use of spare cash while a high-rate debt exists. Whatever the debt is — a personal loan, car finance, or the kind of stubborn card balance this country knows too well — the first step to clearing it is seeing the arithmetic.
Month-by-Month, Interest First
The scheduled repayment is derived from the standard amortisation formula: Payment = Principal × r ÷ (1 − (1 + r)^−n), where r is the monthly rate (annual rate ÷ 12) and n is the term in months — the same formula Australian lenders use to quote P&I repayments. The simulation then walks the loan forward one month at a time. Each month, interest accrues on the chargeable balance — for the offset scenario, that is the loan balance minus the offset amount, because Australian offset arrangements calculate interest on the net figure. The interest is added, then the scheduled payment plus your extra repayment is subtracted. The loop counts months until the balance reaches zero and totals every cent of interest along the way. Two scenarios run in parallel: the plain schedule (no extras, no offset) as the baseline, and your plan. The interest saved is the difference between the two totals; the time saved is the difference in months; the offset contribution isolates how much of the saving came from the buffer alone. One behaviour of Australian loans the model respects: extra repayments have no compounding 'magic' — they simply buy down principal earlier, and the compounding works in reverse, shrinking every subsequent month's interest charge. The one scenario to watch for is a payment too small relative to the rate: if the scheduled payment barely exceeds the monthly interest, the timeline stretches toward never, which the tool flags rather than hiding.
Expert Insights
Extra Repayments Hit Hardest Early
Interest is charged on the balance you owe, so every dollar of extra repayment in month one removes that dollar from every future interest calculation. A $200 monthly extra on a five-year loan saves roughly three times as much interest as a $200 extra introduced in year four. If you can only choose one year to boost payments, make it the first year — or better, start now and keep it constant; the tool shows how constant extras bend the entire curve.
Offset Is a Loan-Rate Return, Tax-Free
A dollar in an offset account against an 11% loan saves 11% — and unlike interest earned in a savings account, the saving is not assessable income. For a borrower on a 30% marginal rate, a savings account paying 4.5% is worth only about 3.1% after tax. Until the debt is gone, parking emergency cash or savings in the offset routinely beats any savings account on a post-tax basis. Check your product: the offset benefit only exists if your loan actually has one, though redraw achieves a near-equivalent effect.
The Rate Is the Real Enemy, Not the Balance
A $12,000 balance at 19.9% costs more in annual interest than a $30,000 balance at 7%. Before optimising payment schedules, question the rate itself: can the debt be refinanced, or (for cards) moved to a balance-transfer promotion or a lower-rate consolidation loan? Run the payoff schedule at the current rate to see what the rate is costing you in raw dollars — that figure is your negotiating leverage when calling a lender to ask for a lower rate.
Actionable Tips
- 1
Get the Exact Payout Figure, Not the Balance
Statements show a balance; lenders quote a payout figure that includes accrued interest and any discharge fees. For planning the final push, call for the payout figure — and check whether your loan has early repayment costs (rare on variable Australian personal loans, possible on some fixed car loans). Knowing the real number to aim at turns the last months from guesswork into a countdown.
- 2
Automate the Extra, Not Just the Minimum
Set the scheduled repayment and the extra as two separate automatic debits on payday. If the extra sits in your everyday account it will be spent; if it leaves automatically the day after pay, the accelerated plan runs whether motivation is high or low. Review once a quarter and increase the extra by whatever pay rises or cost cuts allow.
- 3
Send Windfalls to the Debt
Tax refunds, bonuses, and birthday money are lump-sum principal payments, and they compress timelines more than any budget tweak. A $2,000 lump payment early in the loan erases as much future interest as months of grinding. Route at least half of every windfall to the debt, keep the monthly plan untouched, and watch the payoff date jump backward for free.
Real-World Examples
Sarah's $200 Changed a Five-Year Loan Into Three
Sarah owed $28,000 on a personal loan at 11.5% over five years, paying $617 a month and scheduled to pay $9,000 in interest. She added $200 a month automatically after payday. The loan cleared in 3 years and 4 months with $5,900 of interest — $3,100 saved and 20 months freed. The windfall: when the loan cleared, she redirected the full $817 into her super, which would otherwise have waited two more years.
Dev's Offset Quietly Did the Job
Dev had a $35,000 car loan at 8.4% and kept $5,000 of savings 'for emergencies' in a savings account earning 4.5% — while paying 8.4% on money he effectively already had. Moving the buffer into the loan's offset (same access, same safety) cut his interest charges as if the loan were $30,000, saving him about $25 a month. Combined with a $200 monthly extra, the seven-year loan ended in five and a half. He describes the offset as 'paying his debts with money that is still his'.
Linda Finally Beat the Card
Linda carried $12,000 on a card at 19.9% and had been paying a bit over the minimum for two years with the balance barely moving. Running the schedule showed the true picture: at $310 a month, nearly four years and over $3,000 of interest ahead. She consolidated the card into a 10.5% personal loan over three years, added $100 a month, and cleared it in two and a half years. The tool's baseline number — not the consolidation itself — was the moment the plan became inevitable.
Glossary of Terms
- Amortisation
- The process of paying off a loan through regular payments that cover that month's interest first, with the remainder reducing principal — the structure of standard P&I loans.
- Offset Account
- A transaction or savings account linked to a loan whose balance is subtracted from the loan before interest is calculated, reducing interest charges while leaving the cash accessible.
- Extra Repayment
- Any payment above the scheduled minimum, applied directly to principal. Because future interest is calculated on the lower balance, early extras save the most total interest.
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.