Mortgage Repayment Calculator
Estimate your regular mortgage payment, total interest, and how extra repayments can shorten your loan term.
How this calculator for mortgage repayments works
This mortgage calculator estimates the repayment amount using standard amortization math. That means each payment includes both interest and principal. At the beginning of a loan, more of each payment goes toward interest. Over time, more goes toward reducing the principal balance.
Inputs you can adjust
- Loan amount: the total borrowed amount.
- Interest rate: annual percentage rate used to calculate periodic interest.
- Loan term: how long you plan to repay (for example, 20 or 30 years).
- Repayment frequency: monthly, fortnightly, or weekly payments.
- Extra repayment: optional additional amount each period to pay the mortgage faster.
Why repayment frequency matters
Some borrowers choose fortnightly or weekly repayments because they can align better with salary cycles. More frequent payments may also reduce interest slightly because principal is reduced earlier throughout the year.
In this tool, repayment frequency changes:
- The number of payment periods per year, and
- The interest charged each repayment period.
Understanding your results
After calculation, you will see:
- Regular repayment: the estimated amount due each period.
- Total paid: the full amount repaid over the selected term or faster if extra payments are added.
- Total interest: total borrowing cost.
- Estimated payoff date: when the mortgage reaches a zero balance.
- Interest and time savings: if you include extra repayments.
Practical ways to reduce mortgage interest
1) Add a consistent extra amount
Even an extra $50 to $200 per repayment can compound into major savings over decades.
2) Keep your repayment amount steady after refinancing
If you secure a lower rate, keep paying the old amount. The difference becomes an automatic principal reduction.
3) Review rates regularly
Mortgage rates change. A periodic review can reveal opportunities to refinance or renegotiate with your lender.
Common mistakes when estimating mortgage repayments
- Ignoring additional homeownership costs (maintenance, insurance, taxes, HOA/strata fees).
- Assuming today’s variable interest rate will stay constant forever.
- Borrowing up to the maximum approval amount without budgeting for lifestyle goals.
- Not stress-testing repayments against a higher interest rate scenario.
Bottom line
A good mortgage repayment plan is not just about finding a payment you can afford today. It is about creating a strategy that stays affordable and flexible over many years. Use this calculator often—especially before buying, refinancing, or adjusting your repayment schedule.