Enter your loan details to see your monthly and fortnightly repayments. The calculator shows how much goes toward interest and principal over the life of your loan.
Your mortgage repayment is calculated using an amortisation formula that factors in your loan principal, interest rate, and loan term. Each repayment covers both interest (calculated on the remaining balance) and a portion of principal. Early in the loan, most of your repayment goes to interest — this ratio gradually shifts as you pay down the balance.
With the RBA cash rate at 4.10% as of March 2026, most variable rate mortgages sit between 6.0% and 7.0%. A 0.25% rate increase on a $600,000 loan adds roughly $95-100 per month to repayments. Since February 2025, back-to-back hikes have increased typical repayments by $200-250 per month compared to early 2025 levels.
Tip: Switching from monthly to fortnightly repayments (half the monthly amount each fortnight) means you make 26 half-payments per year instead of 12 full payments — equivalent to one extra monthly payment annually. On a $600,000 loan at 6.5%, this could save you over $100,000 in interest and cut 5+ years off your loan.
If your repayments are consuming more than 30% of your gross household income, you may be in mortgage stress territory. Start with our Mortgage Stress Calculator to assess your position, then explore options like refinancing, switching to interest-only temporarily, or contacting your lender's hardship team.