Estimate a debt payoff date, total interest, and the time and interest potentially saved by recurring or one-time extra principal payments.
This calculator creates a monthly payoff schedule from the current balance, annual interest rate, and required payment. Optional recurring and payment-number-based extra amounts are applied directly to principal after the scheduled payment.
The model assumes a fixed rate, monthly interest, no new charges, and consistent payments. Credit-card and lender calculations can differ because of daily interest, statement timing, fees, and payment-allocation rules.
Beginning balance × annual rate ÷ 12Scheduled payment + extra payments − monthly interestBeginning balance − principal paidCompare a $300 minimum payment with and without an additional $100 each month. The result shows how the higher principal reduction changes payoff time, total interest, and the final payment. Add a one-time payment by selecting the payment number when it will be applied.
When a lender applies extra money to principal without a penalty, the lower balance generally reduces later interest and shortens payoff.
The snowball approach prioritizes the smallest balance first while maintaining required payments on other debts. It can provide visible milestones but may not minimize interest.
The avalanche approach prioritizes the highest interest rate first while maintaining other required payments. It often reduces interest more, though individual circumstances and motivation differ.
Recurring extras are included every month until payoff. One-time extras are applied after the scheduled payment in the selected payment month. Any extra amount is capped at the remaining amount due, so the balance never becomes negative.
The calculator applies monthly interest, the scheduled payment, and any recurring or one-time extra principal payment until the balance reaches zero.
If the payment does not cover accrued interest, principal cannot decline and a payoff schedule would not converge.
Extra principal lowers the balance used for later interest calculations, which can reduce both interest and payoff time.
Yes. Add an amount and the numbered monthly payment when it should be applied. Multiple entries in the same month are combined.
It prioritizes the smallest debt balance while required payments continue on other debts.
It prioritizes the highest-rate debt while required payments continue on other debts.
Prioritizing higher rates often reduces interest more, but rates, balances, required payments, fees, and actual behavior determine the result.
Lenders may use daily interest, different posting dates, fees, minimum-payment rules, rounding, or payment allocation methods.
No. It assumes no new charges and does not model late fees, annual fees, or changing minimum payments.
Yes. The schedule caps the last payment at the remaining balance plus that month’s interest.