Australian Home Loan Repayment Calculator

Your monthly repayment comes from the standard amortisation formula, rounded to the cent. Weekly and fortnightly amounts are then converted from that monthly figure, because that is what Australian lenders document. Interest is worked out daily on your balance at your rate divided by 365. Each month's daily interest is added to the loan on the last day of the calendar month. Lenders vary on the exact day they charge interest, so your statement can differ by a few dollars over the life of the loan. Repayments, extra repayments and offset balances are simulated day by day across the whole loan, so their effect on interest and payoff time is exact for the inputs you give.

Because lenders do it in two different ways, and the difference is large. Dividing the yearly total by 26 keeps your yearly amount the same as paying monthly. Halving the monthly repayment and paying it 26 times means about 13 monthly repayments a year. You pay roughly 8% more each year and clear the loan years earlier. Some lenders have no fortnightly repayment amount at all, because the contract is monthly and paying fortnightly is only how you fund it. Check your loan documents to see which one applies to you.

A little. Interest is charged on your balance each day, so paying earlier in the month leaves a smaller balance for the rest of it. Take a $600,000 loan at 6% over 30 years, keeping your yearly total the same. Moving from monthly to fortnightly is worth roughly $12,500 and finishes the loan about four months early. Moving to weekly is worth roughly $14,600 and about five months. The much bigger saving people put down to paying fortnightly usually comes from something else: paying half a monthly repayment 26 times a year. That is an extra month of repayments every year, not a timing effect.

Because the minimum repayment and the interest are worked out on different calendars. The monthly repayment is the standard formula every lender quotes, which assumes twelve equal months. Interest is charged on the actual days in each month, leap days included. Over a long loan that adds up to a little more than the formula allows for. So if you pay only the minimum, the balance outlasts the term by one repayment, and the last one is a smaller closing payment. Lenders see the same thing. Most borrowers never notice, because paying even a few dollars above the minimum, a rate change or a single extra repayment absorbs it.

Interest is worked out each day on your loan balance less your offset balance, so money sitting in your offset lowers that day's interest. Interest you do not pay is never added to the loan, so your repayment clears more principal and the loan ends earlier.

Yes. Choose "A loan I already have". Enter the balance your lender shows today, the years and months left on the term, your rate and the repayment your lender actually debits. You do not need the loan's history, because none of it changes a future repayment. The calculator runs forward from today on those figures and shows the minimum repayment for that term beside the amount you pay. If your repayment is too small to cover the interest, it says so rather than showing a payoff date. Interest accrued since your last statement is not included, which is at most one month of interest.

They work differently. A lump sum is paid straight off the loan on the date you choose. From that day the balance is lower, so every day of interest after it is lower too, and the loan ends sooner. The money goes into the loan and cannot be taken back. An offset account is savings held against the loan. Interest is charged each day on the loan balance less the offset balance, so the saving is similar while the money sits there, but it stays yours to spend. The calculator models one lump sum and a 100% offset, and measures both against the same loan with neither.

Your loan reverts to principal and interest over the remaining term. The new repayment is worked out on what you still owe at that point, which is what lenders do. If you paid nothing off during the interest-only period, that is the full amount borrowed. Your repayment then steps up noticeably, because the same principal is repaid over fewer years. Any extra repayments you made during the period reduce it. During the interest-only period itself, the calculator pays the interest that actually accrued between repayment dates. So the amount varies a little with the days in each month, and the balance does not drift.