A = P × r / (1 − (1 + r)⁻ⁿ), recalculated when the rate changes.
DECLINING BALANCE · UP TO 35 YEARS
Loan calculator
Model promotional and floating-rate periods, a principal grace period and two common repayment methods.
Affordability stress testHousehold income and a higher-rate scenario+
Formula used
Principal per period = opening principal / principal-payment periods; interest = opening balance × monthly rate.
Only interest is paid during the grace period; principal is allocated across the remaining periods.
Sources and formulas
Model assumptionsAnnual rates are divided by 12; payments occur at month-end; fees, loan insurance, penalties and holiday-driven date changes are excluded.