Loan repayment calculator
See what your loan really costs.
Estimate your repayments, then see how extra repayments and an offset account could reduce the interest you pay and bring your payoff date forward. Everything runs in your browser, and nothing you enter is saved or sent.
RBA cash rate: 4.35% (as at August 2026)
How the loan repayment calculator works
Your repayment is the fixed amount that pays off the loan over its term. It is worked out from three things: the amount you borrow, the interest rate, and the number of repayments. Each period, interest is charged on the balance still owing, your repayment covers that interest, and the rest reduces the balance.
Extra repayments go straight onto the balance, so you owe less and are charged less interest for the rest of the loan. That is why a small amount extra each period can take years off the term and save a large amount of interest.
An offset account is a savings account linked to your loan. The balance in it is subtracted from your loan balance before interest is worked out, so money sitting in the offset reduces your interest without being paid onto the loan itself.
Worked example: A $400,000 loan at 6.00% over 30 years, paid monthly, works out to about $2,398.20 a month. Paying an extra $200 each month clears the loan several years early and saves tens of thousands in interest, because every extra dollar reduces the balance that interest is charged on.
Assumptions
- Interest is calculated each repayment period on the balance owing, reduced by any offset balance.
- The interest rate is assumed to stay constant for the full loan term.
- The offset balance is only ever treated as reducing interest up to the loan balance, never below zero.
- Loan fees are added to your repayment and total cost, but are not added to the loan or charged interest.
Frequently asked questions
How much can extra repayments save on a mortgage in Australia?
It depends on your balance, rate, and how much extra you pay, but the effect compounds. On a typical 30-year loan, an extra $100 to $200 a month can save tens of thousands in interest and take several years off the term. Enter your own figures above to see your result.
How does an offset account reduce mortgage interest?
Interest is charged on your loan balance minus the balance sitting in your linked offset account. If you owe $500,000 and hold $20,000 in the offset, you are only charged interest on $480,000. The money stays available to you and is not paid onto the loan.
Are weekly or fortnightly repayments better than monthly?
Paying more frequently gives only a small interest saving on its own, because the annual amount you pay is essentially the same. The popular larger saving comes from paying half your monthly repayment each fortnight, which adds up to one extra monthly payment a year. You can model that here by putting the difference into the extra repayments field.
Does this calculator include fees?
You can enter a loan fee and choose whether it is charged monthly or annually. The fee is added to your displayed repayment and to the total cost of the loan, but it is not added to the loan balance and does not accrue interest.
What interest rate should I use?
Use the actual rate on your loan, or a rate you have been quoted. Because rates change, it is worth checking the result at a slightly higher rate too, so you know your repayments would still be manageable.
Related reading
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Important
The results from this calculator are estimates for general information and education only. They are based on the assumptions stated and the figures you enter, and do not take your personal circumstances, lender policies, or eligibility into account. They are not financial advice, credit assistance, or an offer of credit. Speak to a licensed finance broker or your lender before making decisions. Broker Codex is a directory platform and does not provide credit assistance.