Two loans, compared on the three numbers that decide which is cheaper: the repayment, the total interest, and the total cost.
The reason for comparing all three is that they can disagree. A loan with a lower repayment is frequently the more expensive loan, because the repayment was lowered by extending the term.
Compares two home loans on repayment, total interest and total cost, so the difference between them is explicit.
Two independent loans
Each has its own amount, rate, term and repayment frequency. They do not have to match — comparing a 30-year loan against a 25-year one is often exactly the question.
Look at total cost first. It is the only figure that captures both the rate and the term, and it is the one a lower monthly repayment can hide.
Then look at the repayment difference, because affordability is a real constraint and the cheapest loan you cannot service is not an option.
The gap between those two readings is the actual decision: how much more per month you are willing to pay to save how much overall.
Every figure below is computed by the same calculator on this page, from the inputs described. Nothing here is typed in by hand, so an example cannot disagree with the tool.
The second loan has the lower rate and the lower repayment, and costs more in total. This is the comparison that a repayment figure alone gets wrong.
Each loan is amortised independently using the standard formula, at its own rate, term and frequency.
Where the frequencies differ, totals are compared over the full life of each loan rather than per period, since per-period figures at different frequencies are not comparable.
Fees are excluded from both
Application fees, annual package fees and discharge fees are real and can reverse a close comparison. A 0.1% rate difference on a $650,000 loan is roughly the size of a typical package fee.
Both rates hold for the full term
Comparing a fixed rate against a variable one at today’s levels compares one known number against one guess.
The comparison rate is a different thing
A lender’s advertised comparison rate folds certain fees into a rate on a standardised loan size and term. It is useful for ranking advertised products and is not what this calculates.
Features are not valued
An offset account, redraw, or the ability to make unlimited extra repayments can be worth more than a small rate difference. None of that appears in a total-cost comparison.
Works out the regular repayment on a home loan, and what it adds up to in interest over the full term.
Compares your current loan with a refinance offer over the same remaining term, and shows how long the switching costs take to recover.
Works out repayments and total interest for a loan split across two portions, each with its own rate, term and repayment frequency.
Estimates what holding a balance in a full offset account saves in interest, and how much sooner the loan closes if repayments stay the same.
This calculator can be embedded on a business website, branded to match it, with a call to action that sends the enquiry to that business rather than collecting anything here.