Estimate how long it will take to pay off a debt from balance, APR and monthly payment, with optional extra payment and fee fields kept visible.
Monthly rate = annual rate ÷ 12. Each month: interest = balance × monthly rate; new balance = balance + interest + monthly fee − monthly payment − extra payment. Repeat until the balance reaches zero, or report that the payment does not cover monthly interest and fees.
With an 8,000 balance and 18.9% APR, the first estimated monthly interest is 8,000 × (0.189 ÷ 12), or 126.00. A 350 regular payment plus 100 extra reduces the first-month balance by about 324.00 after interest. Repeating the same monthly rule gives an estimated 22-month payoff and about 1,459.62 of interest and fees.
Master’s Tip: print one report with the current payment and one with the extra-payment plan. The useful comparison is not just the lower payoff date; it is the interest avoided by paying more than the minimum.
Standard or basis: transparent monthly debt-amortisation arithmetic using user-entered APR, fixed monthly payment, optional extra payment and optional monthly fee. It does not claim compliance with any credit disclosure, lender allocation or hardship-assistance rule.
Methodology & Accuracy
CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.
Monthly rate = annual rate ÷ 12. Each month: interest = balance × monthly rate; new balance = balance + interest + monthly fee − monthly payment − extra payment. Repeat until the balance reaches zero, or report that the payment does not cover monthly interest and fees.
Standard or basis: transparent monthly debt-amortisation arithmetic using user-entered APR, fixed monthly payment, optional extra payment and optional monthly fee. It does not claim compliance with any credit disclosure, lender allocation or hardship-assistance rule.
Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.Master’s Tip: print one report with the current payment and one with the extra-payment plan. The useful comparison is not just the lower payoff date; it is the interest avoided by paying more than the minimum.
Estimate monthly interest from the APR, add any monthly fee, subtract the planned payment and repeat month by month until the balance reaches zero.
If the payment does not cover estimated monthly interest and fees, the balance will not fall. The calculator reports that the debt is not being paid down under those assumptions.
Yes. Extra payment lowers the remaining balance faster, so future monthly interest is usually lower. The exact saving depends on the rate, timing and lender rules.
No. This page uses a fixed monthly payment. Credit-card minimums often change with balance, fees and issuer rules.
No. It uses a monthly estimate and only includes a simple optional monthly fee. Check statements or lender tools for official payoff figures.
Debt payoff arithmetic is a month-by-month balance ledger. It is useful because the borrower can see how much of a payment survives after interest and fees, and how an extra payment changes both payoff time and total interest.
A debt balance usually grows by interest before a payment reduces it. That is why the calculator repeats the same monthly rule instead of simply dividing balance by payment.
If monthly interest and fees are larger than the payment, the balance cannot fall under the entered assumptions. Showing that failure condition is more useful than returning a false payoff date.
An extra payment does not only reduce this month’s balance. It can also lower the interest charged in later months because the future balance is smaller.
Payoff estimates are easy to misunderstand when the rate, payment, extra payment and fee basis disappear. The report keeps those fields beside the result so the plan can be compared with a statement or lender payoff quote.