Paying a Lump Sum Off Your Mortgage in Australia (2026)
A lump sum payment applied directly to your home loan principal can save thousands in interest and cut years from your loan term. Whether it’s a tax refund, work bonus, inheritance, or proceeds from selling an asset — here’s how to make the most of it.
Why Lump Sum Payments Are So Effective
Mortgage interest is charged daily on the outstanding loan balance. When you reduce the principal with a lump sum, you reduce the base on which every future day’s interest is calculated — and the savings compound over the remaining loan term.
The earlier you make the lump sum payment, the more it saves.
$700,000 loan at 6%, lump sum of $20,000 applied at different stages:
| When applied | Interest saved | Time saved |
|---|---|---|
| Year 1 | ~$47,000 | ~2.2 years |
| Year 5 | ~$40,000 | ~1.8 years |
| Year 10 | ~$30,000 | ~1.3 years |
| Year 20 | ~$12,000 | ~7 months |
Estimates only. Assumes constant 6% rate.
Common Sources of Lump Sums
| Source | Timing | Typical amount |
|---|---|---|
| ATO tax refund | August–October (after lodging tax return) | $1,000–$5,000+ |
| Annual work bonus | Year-end or mid-year | Varies |
| Inheritance | Unpredictable | Varies |
| Asset sale (car, shares) | Varies | Varies |
| Government payment (baby bonus, FHOG) | At property purchase | $10,000–$30,000 |
| Property settlement surplus | At sale of prior property | Potentially large |
How to Apply a Lump Sum to Your Loan
Variable Rate Loan — No Restrictions
On a variable rate loan, you can typically make a lump sum payment at any time with no fee or penalty. Options:
- Online banking BSB/account number transfer — use your home loan account details
- BPAY — most lenders have a BPAY biller code for loan repayments
- Branch — in-person payment
- Phone banking — transfer via the lender’s phone service
The payment is credited to your loan immediately and interest is recalculated from the next daily calculation.
Fixed Rate Loan — Check Your Limit First
Fixed rate loans typically allow extra repayments of up to $10,000 per year above the minimum. Paying more than this cap may trigger break costs (also called break fees or economic costs) based on the difference between your fixed rate and current wholesale rates.
Before making a large lump sum on a fixed rate loan:
- Call your lender and ask: “How much can I repay early without break costs?”
- Ask for a break cost estimate if you want to exceed the cap
- Decide whether the interest saving justifies the break cost
→ See What Happens If I Pay Off My Fixed Rate Early?
Lump Sum vs Offset Account
If your loan has an offset account, you have a choice:
| Option | Benefit | Trade-off |
|---|---|---|
| Pay into the loan directly | Permanent principal reduction | Funds locked in (only accessible via redraw) |
| Park in offset account | Same interest saving, full flexibility | Requires discipline not to spend |
For most owner-occupied borrowers: If you are certain you won’t need the funds in the next few years, paying directly into the loan is fine. If you want flexibility (emergency fund, investment opportunity), keep in offset.
For investment property loans: Use offset — direct extra repayments can create tax complications if you later redraw for personal purposes.
Lump Sum Impact Examples
Tax refund of $3,000 on $500,000 loan at 6%:
- Monthly interest saving: ~$15
- Over remaining 25-year term: ~$7,000 total interest saved
- Time saved: ~3 months
Bonus of $25,000 on $700,000 loan at 6%:
- Annual interest saving: $1,500
- Over remaining 20-year term: ~$34,000 total interest saved
- Time saved: ~1.5 years
Inheritance of $100,000 on $600,000 loan at 6%, Year 5:
- Loan balance becomes $500,000 immediately
- Annual interest saving: $6,000
- Over remaining 25-year term: ~$100,000+ total interest saved
- Time saved: ~5–6 years
Should I Pay Down the Mortgage or Invest?
A lump sum doesn’t have to go to the mortgage. The decision to apply funds to the mortgage vs invest in shares or super depends on:
- Your mortgage interest rate vs expected investment return (after tax)
- Your risk tolerance
- Whether you have non-deductible debt (mortgage on your own home) vs deductible debt (investment loan)
→ See Should I Pay Off My Mortgage or Invest?
Frequently Asked Questions
Will paying a lump sum change my repayment amount?
On most Australian loans, a lump sum payment reduces the outstanding balance but does not automatically reduce your minimum required repayment. You continue to pay the same minimum — the loan simply pays off faster. Some lenders do recalculate repayments periodically.
Is there a maximum lump sum I can pay on a variable loan?
Generally no — variable rate loans allow unlimited extra repayments. Some lenders have a maximum single transaction limit (e.g., $100,000 via BPAY) — split into multiple payments if needed.
Does a lump sum affect my LVR or LMI refund?
Paying a lump sum reduces your outstanding loan balance and therefore your LVR. However, Lenders Mortgage Insurance (LMI) premiums paid at origination are not refunded when you reduce your LVR — LMI is a one-time payment regardless of how quickly you repay.
Related Guides
- Extra Repayments — How Much Do They Save?
- What Happens If I Pay Off My Fixed Rate Early?
- Redraw Facility Explained
- Should I Pay Off My Mortgage or Invest?
- Mortgage Repayment Hub
Worked examples are estimates assuming a constant interest rate throughout. Actual savings depend on loan rate, calculation method, and timing. Tax implications of lump sum repayments on investment property loans — speak with a registered tax agent. For advice tailored to your situation, speak with a licensed mortgage broker. Find one through MoneySmart.