Mortgage · Calculator

Mortgage calculator Australia

Calculate your home loan repayments and see how extra payments can save you thousands in interest and years off your mortgage. Weekly, fortnightly, and monthly options.

P&I and interest-onlyExtra repayment savingsAmortisation schedule
01INPUTS

Principal you intend to borrow.

Headline rate — comparison rate may differ.

Adds on top of every scheduled payment; reduces total interest.

02RESULTS
Monthly repayment$3,062.34
Total interest over loan$602,444
Total paid (principal + interest)$1,102,444
Payoff time30.0 years (360 monthly payments)
03SCHEDULE

Amortisation schedule

PeriodPaymentPrincipalInterestBalance
1$3,062.34$479.01$2,583.33$499,520.99
2$3,062.34$481.49$2,580.86$499,039.50
3$3,062.34$483.97$2,578.37$498,555.53
4$3,062.34$486.47$2,575.87$498,069.05
5$3,062.34$488.99$2,573.36$497,580.07
6$3,062.34$491.51$2,570.83$497,088.55
7$3,062.34$494.05$2,568.29$496,594.50
8$3,062.34$496.61$2,565.74$496,097.89
9$3,062.34$499.17$2,563.17$495,598.72
10$3,062.34$501.75$2,560.59$495,096.97
11$3,062.34$504.34$2,558.00$494,592.62
12$3,062.34$506.95$2,555.40$494,085.67
355$3,062.34$2,969.11$93.24$15,077.22
356$3,062.34$2,984.45$77.90$12,092.78
357$3,062.34$2,999.87$62.48$9,092.91
358$3,062.34$3,015.36$46.98$6,077.55
359$3,062.34$3,030.94$31.40$3,046.60
360$3,062.34$3,046.60$15.74$0.00
How mortgage repayments work

Each mortgage repayment consists of two parts: principal (paying down the loan) and interest (the cost of borrowing). In the early years, most of your payment goes to interest. As the loan balance decreases, more goes to principal.

Principal & Interest (P&I)

The standard loan type. Each payment reduces your loan balance and covers interest. Most owner-occupier loans are P&I.

Interest Only (IO)

You only pay interest for a set period (usually 1–5 years). The loan balance doesn't decrease. Often used by investors.

The power of extra repayments

Making extra repayments is one of the most effective ways to pay off your mortgage faster. On a $500,000 loan at 6% over 30 years:

Extra $100/month

~$45,000

interest saved · 4 years early

Extra $200/month

~$80,000

interest saved · 7 years early

Extra $500/month

~$140,000

interest saved · 12 years early

Weekly vs fortnightly vs monthly

A more frequent repayment schedule can save you money without increasing your monthly budget.

Monthly — 12 payments per year — the standard.
Fortnightly — 26 payments per year, equivalent to 13 monthly payments. The extra payment goes directly to principal.
Weekly — 52 payments per year — same net effect as fortnightly but with smaller individual amounts.
Fortnightly vs monthly repayments

Setting your fortnightly repayment to exactly half your monthly amount — rather than a quarter of an annual figure — is the trick that makes fortnightly repayments save real money. Because there are 26 fortnights in a year, you end up making the equivalent of 13 monthly payments instead of 12, with the extra payment going straight to principal.

Monthly (12/yr)

$3,062.34

30 years · $602,444 total interest

True fortnightly (26/yr)

$1,531.17

~24.4 years · ~$469,569 total interest

On a $500,000 loan at 6.2% over 30 years, true fortnightly repayments pay the loan off roughly 5.6 years sooner and save about $132,876 in interest compared with the standard monthly schedule. See our fortnightly vs monthly repayments guide for the full breakdown, including why some lenders' "fortnightly" default doesn't actually deliver this saving.

Understanding your amortisation schedule

Every mortgage repayment splits between interest and principal, and that split changes across the life of the loan. In the early years, most of each repayment covers interest on the large outstanding balance — on a $500,000 loan at 6.2%, the very first monthly repayment of $3,062.34 is $2,583.33 interest and just $479.01 principal.

As the balance falls, the interest portion of each repayment shrinks and the principal portion grows, until the two cross over — typically past the halfway point of a 30-year term. This is why extra repayments made early in the loan have an outsized effect: every dollar of extra principal in year one stops accruing interest for the remaining 29 years.

Run your own numbers and see the full month-by-month interest/principal split below the calculator above, or read our amortisation schedule guide for a worked walkthrough.

Repayments at a glance

Indicative monthly principal & interest repayments at 6.2% p.a. over a 30-year term, for common loan sizes:

Loan amountMonthly repayment
$300,000 $1,837
$500,000 $3,062
$750,000 $4,594
$1,000,000 $6,125

Based on the reference rate in the calculator above (6.2% p.a., last reviewed 2026-05-02). Your actual rate depends on your lender, LVR, and loan type — use the calculator to model your own figures.

FAQ
How is mortgage repayment calculated?
Mortgage repayments are calculated using the PMT formula: P × (r(1+r)^n) / ((1+r)^n - 1), where P is the principal, r is the periodic interest rate, and n is the total number of payments. This gives you the fixed payment needed to pay off the loan over the term.
Should I make weekly or monthly repayments?
Weekly or fortnightly repayments can save money because you make more payments per year. Fortnightly payments are equivalent to 13 monthly payments per year instead of 12, helping you pay off your loan faster.
What is a comparison rate?
The comparison rate includes both the interest rate and most fees and charges, giving you a more accurate picture of the true cost of a loan. Always compare loans using the comparison rate rather than just the headline rate.
What is an offset account?
An offset account is a transaction account linked to your mortgage. The balance offsets your loan balance for interest calculations. For example, $50,000 in offset against a $500,000 loan means you only pay interest on $450,000.
Should I fix my interest rate?
Fixed rates provide certainty — your repayments won't change during the fixed period. However, you may miss out if rates drop, and there are often restrictions on extra repayments. Many borrowers split their loan between fixed and variable.
Should I pay my mortgage fortnightly or monthly?
Fortnightly repayments set to half your monthly amount make 26 half-payments a year — the equivalent of 13 monthly payments instead of 12. On a $500,000 loan at 6.2% over 30 years, that turns a $3,062.34 monthly repayment into a $1,531.17 fortnightly one, cutting the loan to about 24.4 years and saving roughly $132,876 in interest versus the standard 30-year monthly schedule. The saving comes purely from the extra annual payment, not from paying more per year on a pro-rata basis.
What is an amortisation schedule?
An amortisation schedule breaks every repayment into its interest and principal components across the life of the loan. Early payments are interest-heavy — on a $500,000 loan at 6.2%, the first monthly repayment of $3,062.34 is $2,583.33 interest and only $479.01 principal. As the balance shrinks, the interest portion falls and the principal portion grows, with the two crossing over roughly halfway through a 30-year term.

Tax Accuracy & Sources

Reviewed: March 2026 · Tax year: 2026-27

Estimates mortgage repayments and interest using the standard PMT formula. Does not account for lender fees, comparison rates, lenders mortgage insurance, offset account interest calculations, or redraw facilities.

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