$300,000 Mortgage at 4.5%
See exactly what you'll pay on a $300,000 home loan at 4.5% interest. Monthly, fortnightly, and weekly repayments with total interest and savings tips.
Last verified: 5 May 2026Monthly repayments on a $300,000 mortgage at 4.5% over 30 years: $1,520.06
Monthly
$1,520.06
Fortnightly
$701.56
Weekly
$350.78
Total cost over 30 years
$547,220
Principal $300,000 + Interest $247,220
Total interest paid
$247,220
82% of the loan amount
25-Year vs 30-Year Term
| 25 years | 30 years | Difference | |
|---|---|---|---|
| Monthly repayment | $1,667.50 | $1,520.06 | +$147.44/mo |
| Total interest | $200,249 | $247,220 | Save $46,971 |
| Total repaid | $500,249 | $547,220 | Save $46,971 |
What If Rates Change?
| Rate | Monthly | Fortnightly | vs current |
|---|---|---|---|
| 4% | $1,432.25 | $661.04 | -$87.81/mo |
| 4.5%(current) | $1,520.06 | $701.56 | — |
| 5% | $1,610.46 | $743.29 | +$90.41/mo |
| 5.5% | $1,703.37 | $786.17 | +$183.31/mo |
| 6% | $1,798.65 | $830.15 | +$278.60/mo |
Income Needed
You'd need a household income of approximately $60,802/year ($5,067/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 $100,176 in interest
- Pays off your loan 10.9 years sooner
Fortnightly vs Monthly Trick
Paying $760.03 fortnightly (half the monthly repayment) instead of $1,520.06 monthly means you make 26 half-payments per year — equivalent to 13 monthly payments instead of 12.
- Interest saved: $42,050
- Time saved: 4.4 years
Frequently Asked Questions
How much are repayments on a $300,000 mortgage?
At 4.5% over 30 years, monthly repayments on a $300,000 mortgage are $1,520.06. Fortnightly repayments are $701.56 and weekly repayments are $350.78.
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 $60,802 per year to comfortably afford a $300,000 mortgage at 4.5%.
How much interest will I pay on $300,000 over 30 years?
At 4.5%, the total interest on a $300,000 mortgage over 30 years is $247,220. The total amount repaid would be $547,220.
What if interest rates rise above 4.5%?
If rates rise by 1% to 5.5%, monthly repayments on a $300,000 mortgage increase to $1,703.37 — an extra $183.31 per month.
Other Mortgage Amounts
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General information and estimates only — not financial, tax, or legal advice. Always verify with a licensed adviser or the ATO.