Calculator methodology

How the Payoff Path calculator works

The calculator creates an educational month-by-month estimate from the balances, APRs, minimum payments, extra monthly payment, and strategy entered.

What it shows

Monthly calculation

For each month, the model estimates interest as the outstanding balance multiplied by APR divided by 12. It then applies each debt’s minimum payment. The remaining fixed monthly budget—including the extra payment and payments freed by earlier payoffs—is directed to the selected target debt.

Avalanche and snowball

Avalanche targets the highest APR first, with balance used to break ties. Within a fixed-rate model, this generally reduces interest. Snowball targets the smallest current balance first, with APR used to break ties, which may provide earlier visible milestones.

Privacy

Calculations run in the browser. Entries are saved in that browser’s local storage and are not submitted to Payoff Path. Use “Clear my saved data” on a shared device.

Important assumptions

Mortgages and changing rates

This calculator is not designed to forecast mortgage renewals, variable-rate changes, qualification, prepayment penalties, or a mortgage’s contractual amortization. For a mortgage nearing renewal, use the projected renewal balance, remaining amortization, offered rate, payment frequency, and applicable fees in an appropriate mortgage calculator. See the Canadian mortgage-renewal guide.

Run an estimate

Use recent statements, then confirm the result with each lender.

Open the calculator

Reviewed: July 2026 · Educational estimates only.