$300,000 Mortgage at 4%
See exactly what you'll pay on a $300,000 home loan at 4% interest. Monthly, fortnightly, and weekly repayments with total interest and savings tips.
Last verified: 5 May 2026Monthly repayments on a $300,000 mortgage at 4% over 30 years: $1,432.25
Monthly
$1,432.25
Fortnightly
$661.04
Weekly
$330.52
Total cost over 30 years
$515,609
Principal $300,000 + Interest $215,609
Total interest paid
$215,609
72% of the loan amount
25-Year vs 30-Year Term
| 25 years | 30 years | Difference | |
|---|---|---|---|
| Monthly repayment | $1,583.51 | $1,432.25 | +$151.26/mo |
| Total interest | $175,053 | $215,609 | Save $40,555 |
| Total repaid | $475,053 | $515,609 | Save $40,555 |
What If Rates Change?
| Rate | Monthly | Fortnightly | vs current |
|---|---|---|---|
| 3.5% | $1,347.13 | $621.75 | -$85.11/mo |
| 4%(current) | $1,432.25 | $661.04 | — |
| 4.5% | $1,520.06 | $701.56 | +$87.81/mo |
| 5% | $1,610.46 | $743.29 | +$178.22/mo |
| 5.5% | $1,703.37 | $786.17 | +$271.12/mo |
Income Needed
You'd need a household income of approximately $57,290/year ($4,774/month) to comfortably afford this mortgage using the 30% rule — where no more than 30% of your gross income goes toward housing costs.
Extra Repayment Impact
Paying an extra $100/week on your $300,000 mortgage:
- Saves $85,654 in interest
- Pays off your loan 10.8 years sooner
Fortnightly vs Monthly Trick
Paying $716.12 fortnightly (half the monthly repayment) instead of $1,432.25 monthly means you make 26 half-payments per year — equivalent to 13 monthly payments instead of 12.
- Interest saved: $33,830
- Time saved: 4.1 years
Frequently Asked Questions
How much are repayments on a $300,000 mortgage?
At 4% over 30 years, monthly repayments on a $300,000 mortgage are $1,432.25. Fortnightly repayments are $661.04 and weekly repayments are $330.52.
What income do I need for a $300,000 mortgage?
Using the 30% rule (no more than 30% of gross income on housing), you would need a household income of approximately $57,290 per year to comfortably afford a $300,000 mortgage at 4%.
How much interest will I pay on $300,000 over 30 years?
At 4%, the total interest on a $300,000 mortgage over 30 years is $215,609. The total amount repaid would be $515,609.
What if interest rates rise above 4%?
If rates rise by 1% to 5%, monthly repayments on a $300,000 mortgage increase to $1,610.46 — an extra $178.22 per month.
Other Mortgage Amounts
Other Interest Rates
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General information and estimates only — not financial, tax, or legal advice. Always verify with a licensed adviser or the ATO.