Loan & mortgage repayment calculator
See your repayments, how much interest you'll pay over the life of the loan, and how much time and money extra repayments save.
Loan balance over time
Principal vs interest
Year-by-year table
How it works
repayment = P × r ÷ (1 − (1 + r)−n)P is the loan amount, r is the annual rate divided by the number of repayments a year, and n is the total number of repayments.
Worked example
A $600,000 mortgage at 6% over 30 years, paid monthly: r = 0.06 ÷ 12 = 0.005 and n = 360. The repayment is $3,597.30 a month. Over 30 years you'd pay about $695,000 in interest – more than the loan itself.
Add $300 a month extra and it’s paid off in about 24 years and 7 months – more than five years sooner – saving roughly $147,000 in interest.
Common questions
How is a loan repayment worked out?
With the standard amortisation formula. Each repayment covers that period's interest first, and the rest pays down the balance. Early on most of it is interest; towards the end most of it is principal.
Is fortnightly cheaper than monthly?
Paying the true fortnightly amount (based on 26 payments a year) saves only a little. Many banks' 'fortnightly' option is half the monthly payment, which adds up to an extra month's repayment each year – that's where the bigger saving comes from. Try it by adding the difference as an extra repayment.
What do extra repayments save?
Every extra dollar goes straight off the balance, so you stop paying interest on it from then on. Even small regular extras can cut years off a mortgage.
Does this include fees or rate changes?
No. It assumes the rate stays the same for the whole loan and leaves out fees, offset accounts and redraw. Use it for a ballpark, and get the comparison rate and full costs from your lender.