$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: 1 July 2025

Monthly 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

$200K mortgage $250K mortgage $350K mortgage $400K mortgage $450K mortgage

Other Interest Rates

$300,000 at 4%$300,000 at 5%$300,000 at 5.5%$300,000 at 6%$300,000 at 6.5%$300,000 at 7%$300,000 at 7.5%$300,000 at 8%

General information and estimates only — not financial, tax, or legal advice. Always verify with a licensed adviser or the ATO.

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