The Exact Numbers — How Much Extra Per Month
| Loan Size | Rate | Standard Term | Extra/Month for 10yr Saving | Interest Saved |
|---|---|---|---|---|
| $400,000 | 6.25% | 25 years | $680/month | $145,000 |
| $550,000 | 6.25% | 25 years | $935/month | $199,000 |
| $700,000 | 6.25% | 25 years | $1,190/month | $254,000 |
| $400,000 | 6.48% | 30 years | $520/month | $196,000 |
| $550,000 | 6.48% | 30 years | $715/month | $270,000 |
| Use our calculator for your exact loan figures | Huge savings | |||
Why Starting Early Makes Such a Difference
The interest saving from cutting 10 years off a mortgage is enormous because you avoid 10 years of compound interest on the remaining balance. On a $550,000 loan at 6.25%, you pay approximately $68,000 in interest in years 16-25 — money you keep entirely by paying off 10 years early. Starting the extra repayments in year 1 rather than year 5 saves an additional $40,000+ in interest on a typical Australian mortgage.
Strategies to Find the Extra Money
- Switch to fortnightly repayments — adds one extra monthly payment per year automatically, no budget impact
- Round up your repayment — if your repayment is $2,847/month, round to $3,000 — $153 extra monthly saves years
- Direct tax refunds to the mortgage — average Australian tax refund is $3,000+ — a powerful annual lump sum
- Review subscriptions and discretionary spending — $300/month of savings on a $550,000 loan cuts 4 years off your term
- Refinance to a lower rate first — then keep your repayment at the old (higher) amount — automatic extra repayment
Is It Better to Invest or Overpay?
At current mortgage rates of 6.25%+, overpaying provides a guaranteed after-tax return equivalent to your mortgage rate. To beat this with investments, you'd need consistent real returns above 6.25% after tax. Australian equities have historically returned 7-10% p.a. over long periods, but with significant volatility. Most financial planners suggest high-income earners consider investing some surplus (for compound growth) while lower-income earners prioritise mortgage overpayment for the guaranteed return. Per ASIC, always get personalised financial advice before making this decision.
Frequently Asked Questions
How many years does $500/month extra save on an Australian mortgage?
On a $550,000 mortgage at 6.25% over 25 years, an extra $500/month saves approximately 7 years and $120,000 in interest. Use our calculator above for your exact loan details.
What is the fastest way to pay off a mortgage in Australia?
The fastest approaches are: switch to fortnightly repayments, make regular extra repayments, apply lump sums (tax refunds, bonuses) directly to principal, and refinance to the lowest available rate. Combining all four can cut a 25-year mortgage to 12-15 years.
Will my lender allow me to pay extra on my fixed rate mortgage?
Most Australian fixed rate lenders allow overpayments up to 10% of the outstanding balance per year without break costs. Exceeding this triggers break fees. Check your loan contract carefully.