$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: 1 July 2025

Monthly 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

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

Other Interest Rates

$300,000 at 4.5%$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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