Repayment · interest · payoff
Home Loan Mortgage Repayment Calculator
Estimate repayments, total interest and how much faster extra payments could clear your mortgage.
Enter your loan details
For a principal-and-interest home loan.
See where the money goes
Repayment breakdown
| Payment | Total paid | Principal | Interest | Extra | Balance |
|---|
Transparent calculation
How mortgage repayments are calculated
For a principal-and-interest home loan, each repayment covers the interest charged for that period and reduces part of the amount borrowed. A standard amortising payment is designed to bring the balance to zero after the selected number of payments.
Find the periodic rate
A 6% annual rate with monthly payments becomes 0.06 ÷ 12, or 0.5% per month.
Calculate the fixed repayment
The formula finds the payment that repays principal and interest over the full term.
Amortise each period
Interest is calculated from the current balance. The rest of the payment reduces principal.
Apply extras to principal
Extra payments reduce the balance sooner, which can lower later interest and shorten the term.
Worked example
$500,000 mortgage at 6% for 30 years
With monthly principal-and-interest repayments and no fees, the scheduled payment is about $2,997.75. Over 360 payments, estimated interest is about $579,190.95.
Adding $200 to every monthly payment would reduce the estimate to about 25 years and 6 months and save roughly $103,145 in interest, assuming the rate stays at 6% and the lender applies extras directly to principal.
With $200 extra$3,197.75About 4 years 6 months sooner
Test a strategy
How extra mortgage repayments can change the result
Extra payments are applied to principal in this model. A lower balance means less interest is charged in future periods. Earlier extras usually have more time to affect the result.
Recurring extra repayment
Add an amount to every weekly, fortnightly or monthly repayment. The calculator keeps the original scheduled repayment and adds your extra.
One-off payment now
Model a lump sum at the start. The regular scheduled amount stays the same, so the reduced balance can be repaid sooner.
Frequency changes
This calculator derives a true payment for the frequency selected. Paying half a monthly amount fortnightly is a different strategy because 26 half-payments equal 13 monthly payments each year.
Know the scope
What this repayment estimate includes
Included in amortisation
Loan principal, the entered annual interest rate, loan term, selected frequency, recurring extras and an optional one-off principal payment.
Shown separately
Optional monthly property taxes, home insurance, mortgage insurance, strata or homeowners-association costs.
Not modelled
Rate changes, lender fees, offset accounts, redraw, daily-interest rules, balloon payments, interest-only periods or tax effects.
A lender's quoted total payment may be higher than principal and interest because it can include taxes, insurance and other charges. Compare the calculator result with the lender's official repayment schedule.
Methodology sources
The tool applies the standard fixed-payment amortisation method and clearly separates principal-and-interest repayments from optional housing costs. Its assumptions follow published consumer guidance.
Common questions
Mortgage repayment calculator FAQ
How are home loan repayments calculated?
The standard formula uses the amount borrowed, periodic interest rate and total number of repayments. Each payment first covers interest for the period; the remainder reduces principal.
Do extra repayments reduce mortgage interest?
Usually, when they are applied directly to principal. Reducing the balance sooner means less interest is charged later. Check for prepayment limits, break costs and fees.
Are taxes, insurance and HOA or strata fees included?
They are not included in the loan amortisation. You can enter a combined monthly estimate so the result shows a broader housing outflow alongside principal and interest.
Is fortnightly always cheaper than monthly?
No. This tool calculates the amortising payment for the selected frequency. A common separate strategy is paying half a monthly repayment every two weeks, which produces 26 half-payments—or 13 monthly payments—per year.
Can I use the calculator for a variable interest rate?
You can test separate rates, but each result assumes the entered rate remains unchanged. It does not predict future rate movements or lender recalculations.
Why might my lender's repayment be different?
A lender may use daily interest, different rounding, fees, an offset balance, a different first period or other contract rules. Use the lender's documents for an exact figure.
Does this calculate an interest-only loan?
No. It is designed for principal-and-interest repayments that gradually reduce the amount borrowed.