Loan repayment calculator
Estimate the weekly, fortnightly or monthly repayment on a home or construction loan, principal and interest or interest only, at any rate and term.
Last updated 14 June 2026
Home loan repayment calculator
Estimate the principal-and-interest or interest-only repayment on a home or construction loan. Change any field to update the result instantly.
$3,164
Principal and interest over 30 years at 6.14%.
This is general information only and does not take into account your objectives, financial situation or needs. It is not credit assistance or a credit quote. Consider whether it is right for you and seek advice. Finance is arranged through Central Lending Solutions, the licensed credit partner The Property Plug works with (Australian Credit Licence or credit representative number [TBC]).
Want this checked against live lender rates?
Talk to our finance team →A loan repayment calculator works out the regular payment needed to clear a loan over its term. The Property Plug calculator uses the standard amortising annuity formula for principal-and-interest loans and a simple interest charge for interest-only loans, across weekly, fortnightly and monthly frequencies. It is general information, not a credit quote.
How the repayment is built
For a principal-and-interest loan, each payment covers the interest on the current balance plus a slice of principal. Early on most of the payment is interest. As the balance falls, more goes to principal. The formula keeps the payment level across the term so your budgeting stays predictable.
- Loan amount (P) is what you borrow after your deposit and any grant.
- Periodic rate (i) is the annual rate divided by the number of payments a year.
- Number of payments (n) is the term in years times the payment frequency.
- Frequency changes both the payment size and the total interest, because more frequent payments reduce the balance sooner.
A $520,000 loan at 6.14%
On a $520,000 principal-and-interest loan over 30 years at 6.14%, the monthly repayment lands near $3,164 and total interest over the term is well over $600,000. Switch to fortnightly and you shave time and interest off the loan. Switch to interest only and the monthly payment drops, but you clear no principal while that period runs.
| Scenario | Repayment | Note |
|---|---|---|
| $520k, 6.14%, 30yr, P&I monthly | about $3,164 / month | Standard structure |
| Same loan, fortnightly | about $1,582 / fortnight | 13 monthly equivalents a year |
| Same loan, interest only | about $2,661 / month | No principal reduction |
| Rate rises to 7.14% | about $3,506 / month | Why lenders buffer |
Indicative figures, rounded. Your rate and terms will differ.
Construction loans repay differently
If you are building, you usually pay interest only on the funds drawn at each stage during the 12 month build, so your early repayments are smaller than this calculator's full principal-and-interest figure. The full repayment kicks in once the build completes and the loan converts. Use interest-only mode to model the build phase, then principal and interest for life after handover.
This is general information only and does not take into account your objectives, financial situation or needs. It is not credit assistance or a credit quote. Consider whether it is right for you and seek advice. Finance is arranged through Central Lending Solutions, the licensed credit partner The Property Plug works with (Australian Credit Licence or credit representative number [TBC]).
How is the repayment calculated?
It uses the standard amortising loan formula: M = P times i divided by 1 minus (1 plus i) to the power of minus n, where P is the loan, i is the periodic interest rate and n is the number of payments. Interest-only mode simply charges the periodic interest on the full balance, with no principal reduction.
Does paying fortnightly really save money?
It can. Paying half the monthly amount every fortnight means you make the equivalent of 13 monthly payments a year instead of 12, so a little extra principal comes off and you save interest over the life of the loan. Our calculator lets you switch frequency to compare.
Why does interest-only cost more overall?
During an interest-only period you do not reduce the principal, so you pay interest on the full balance for longer and the total interest over the loan is higher. Investors still use it for cashflow and tax reasons, but on an owner-occupied home, principal and interest usually costs less over time.
Is the rate I enter the rate I will get?
Not necessarily. Advertised and comparison rates differ by lender, loan type, deposit and whether the loan is owner-occupied or investment. Use a realistic current rate for a guide, then book a call so we can compare live rates across the panel for your situation.
Lock in a repayment you are comfortable with
Book a free finance call. We compare live rates across the panel and structure a loan whose repayment fits your budget through the build and beyond.