Model a debt payoff plan that directs spare payment money to the smallest remaining balance first.
The calculator keeps the balance, rate convention, payment timing, fees, and term visible so you can reproduce the result and compare it with an actual offer or statement.
The cash-flow relationship
Place every amount at the correct time
Each month: add stated interest, make required payments, then direct the remaining budget to the smallest balance.
Visual explanation
What changes the borrowing result
Debt 1Debt 2Debt 3required payments firstextra payment → selected priorityEach month: add stated interest, make required payments, then direct the remaining budget to the smallest balance.
Read the result in context
Use the estimate with its contract assumptions
Compare two or more balances while keeping a fixed extra monthly debt payment.
This is a deterministic estimate using constant APRs and monthly compounding. It excludes new charges, late fees, and lender-specific allocation rules.
Quick guide
How to use this calculator
Enter all amounts in one consistent currency.
Enter annual percentage rates and whole-month counts exactly as labelled.
Review the result together with the stated assumptions and exclusions.
Calculation method
Calculation method
Each month: add stated interest, make required payments, then direct the remaining budget to the smallest balance.
The calculator keeps full binary floating-point precision through the calculation and rounds only for display. It rejects non-amortizing payments, invalid rates, and schedules beyond the disclosed work limits.
Worked example
Practical example
Compare two or more balances while keeping a fixed extra monthly debt payment.
Each month: add stated interest, make required payments, then direct the remaining budget to the smallest balance.
Supported inputs
Precision and limits
Visible input limits
Numeric tokens accept at most 60 characters. Amounts are capped at 1e12 and annual rates at 1000%. Repayment terms are whole months up to 1200; grace, promotional, and lease periods are whole months up to 120.
Estimate, not an offer
Results model only the values entered. Lenders may use different compounding, day counts, fees, payment allocation, or rounding.
International scope
No country, tax system, government benefit, regulated disclosure, or currency is assumed. Enter one consistent currency and verify local terms separately.
Calculator-specific assumptions
This is a deterministic estimate using constant APRs and monthly compounding. It excludes new charges, late fees, and lender-specific allocation rules.
