Mortgage Calculator
Estimate repayments and see how they sit against your surplus.
Affordability snapshot Linked to planner
Compare your share of the mortgage payment to the surplus stored in your main budget.
Planner surplus (est)
From main planner 0
Basis
Your mortgage share
Payment used here 0
Coverage Run a calculation
Surplus after payment 0
Loan details
Adjust the loan amount, rate, and term, then compare to your planner surplus.
Property price
$
Deposit
$
Enter deposit in dollars. Tap the toggle to switch to % of price.
Interest rate (p.a.)
%
Future rate (optional)
%
Loan type
Loan term
years
Repayment frequency
Extra repayment (optional)
$
Split with partner for this calc (use half in affordability)
Mortgages saved into your planner from this tool
No mortgages found yet.
Tap a line to select, edit with the calculator, then press “Save / update mortgage in planner”.
Rough guide only. Does not include fees, changing rates, or lender-specific rules.
Results
Whole-loan repayments, your share if split, total interest, and a future-rate comparison.
Whole loan repayment (including extra)
Per month
Your share used in affordability
Amount
Status Not split
Total interest over life of loan
Current rate
With extra repayments
Estimated time saved with extra
Base term
With extra
Mortgage vs planner surplus
Run a calculation to compare.
Future rate comparison (if you fill the future rate box)
Repayment at future rate
Total interest at future rate
Change vs current
Enter a future interest rate to see how repayments and total interest could change.
Show calculation notes
How this calculator works
  • Loan amount = property price minus your deposit.
  • Repayments use a standard amortising loan formula based on your rate, term, and chosen frequency.
  • Extra repayments are added on top of the base repayment and then used to simulate an earlier payoff.
  • “Your mortgage share” uses half the repayment if the split box is ticked.
  • “Mortgage vs planner surplus” compares your share to the surplus stored in your main planner for W/F/M/Y.
  • The future rate view re-runs the same formula at the alternative rate so you can see how sensitive the loan is to rate changes.