Repayments are the number everyone checks first, and total interest is the number almost nobody does. This calculator shows both, lets you switch between weekly, fortnightly and monthly, compare interest-only with principal and interest, and see what a small extra repayment does to the term and the interest bill over 30 years.
Fortnightly repayments shown here are half the monthly figure, the common lender convention that quietly adds one extra monthly repayment a year.
Fixed rate for the whole term for illustration; real rates move. Interest-only shows the IO repayment first, then the higher P&I repayment that follows.
Get the real number from the team →Every assumption the tool makes, so you can see where your situation differs.
Figures checked October 2026. Rates and thresholds change; the team re-checks before every application.
Principal-and-interest repayments use the standard annuity formula: the loan amount, the monthly rate (annual rate divided by twelve) and the number of months, solved so that the balance reaches zero on the last payment. Interest-only repayments are simply the balance times the monthly rate.
Lenders calculate interest daily and charge it monthly, so real figures differ from this by a few dollars. Fortnightly and weekly repayments are usually set at half or a quarter of the monthly figure, which is why they pay the loan off faster: 26 fortnightly payments equal 13 monthly ones.
Because every dollar paid early stops earning interest for the lender for the rest of the term. On a $650,000 loan at 6.25% over 30 years, an extra $200 a month saves roughly $110,000 of interest and cuts about four years off the loan.
The effect is strongest early, when most of each repayment is interest. An offset account does the same job without locking the money away; see the home loans page on offset versus redraw.
Interest-only lowers the repayment now and raises it later: the same loan has to be repaid over the remaining 25 years, so the step-up at the end of a five-year IO period is steep, and total interest is higher. It suits investors managing cash flow and deductibility, rarely owner-occupiers.
Lenders assess an interest-only loan on the P&I repayment over the shorter remaining term, so it is harder to qualify for, not easier.
The rate you have been quoted, or the rate on your current statement. If you want a market reference, sharp owner-occupier variables sat just above 6% in October 2026 and the average was 6.75%, after four cash-rate rises this year. The team can tell you where your loan sits today.
Straight answers. If yours isn't here, ask cinchi (bottom right) or book a chat.
Roughly how much a lender would let you borrow, with the 3% buffer applied.
Open calculator →03Monthly saving, break-even month and five-year net benefit after switching costs.
Open calculator →05Deposit plus loan, minus duty, LMI and costs: the price you can actually bid to.
Open calculator →AllThe five tools and the cinchi assistant on one page.
See all →Repayments you can plan a life around. A cinch.
I'm cinchi, Cinch Loans' AI assistant. I explain how Australian home loans and finance work, and when a question needs a current figure I check trusted sources like MoneySmart, Housing Australia, the RBA and the state revenue offices, and show you where it came from. Suvidh and the team give the actual advice. Your questions are saved so they can pick up where we left off, and when a question needs a person, I'll put you straight through on WhatsApp.
Conversation ref · pending
cinchi is an AI assistant. It can be wrong. Figures are quoted from the source shown and change over time. Nothing here is personal credit advice or an offer of credit. Credit Guide · Privacy · Talk to Suvidh