Calculator
Loan Repayment Calculator
Estimate repayments, total interest and the effect of rate or term changes before you speak with a lender.
Principal and interest results use a standard amortisation formula. Extra repayments are modelled as reducing the loan balance and shortening the term. Actual lender calculations may differ because of fees, offset balances, repayment timing and rate changes.
Want these numbers checked? Send the result across and we'll tell you what a lender would make of it. No meeting required.
Use this as a guide, then check the structure
A repayment calculator is useful for seeing whether a loan amount is comfortable, but it does not tell you whether a lender will approve the deal or whether the structure is right. Offset accounts, split loans, interest-only periods, repayment buffers and future borrowing plans can change the best answer.
For a proper check, send the result through or book a short finance call.
Frequently asked questions
How are home loan repayments calculated?
A principal and interest repayment comes from a standard amortisation formula using three inputs: the loan amount, the interest rate and the term. Early repayments are mostly interest, and the principal share grows as the balance falls. Interest only repayments are simply the balance multiplied by the periodic rate, so the balance never reduces. This calculator runs both, and shows total interest alongside the repayment so you can see the real cost of the term you pick.
Does paying fortnightly instead of monthly save interest?
It depends on how the fortnightly figure is set. Splitting a monthly repayment exactly in half and paying it 26 times a year means you pay the equivalent of 13 monthly repayments instead of 12, and that extra amount cuts the balance and the total interest. If the fortnightly figure is instead calculated to be exactly equivalent to the monthly one, the saving disappears. Check which one your lender is actually doing before assuming a benefit.
What does interest only cost over the life of a loan?
More, because nothing comes off the balance during the interest only period. The repayment is lower while it runs, then rises when the loan reverts to principal and interest over a shorter remaining term. Interest only has real uses, particularly on investment debt or where cash flow is temporarily tight, but it is a cash flow decision rather than a saving. Switch the repayment type in this calculator to see the total interest difference on your own numbers.
How much difference do extra repayments make?
More than most people expect, because every extra dollar reduces the balance that interest is charged on for the whole remaining term. The earlier in the loan you make them, the larger the effect. Enter an extra repayment in this calculator and it models the reduced balance and shorter term. Before committing to extra repayments, it is worth checking whether an offset account gives you the same interest saving while keeping the money accessible.