Credit Card Payoff Calculator

What this calculator returns

The calculator runs a credit card balance forward at a fixed monthly payment until the balance reaches zero. Each month interest accrues at the monthly rate, meaning the APR divided by twelve, the payment is applied, and the loop continues. The result is the actual number of months to clear, the same figure as years and months, the total amount paid across that period, the total interest, the first month’s interest charge, and the total interest as a share of the original balance. On the defaults, a 5,000 balance at 22% paying 250 a month clears in 26 months, costing 1,285.72 in interest, which is 25.71% of what was borrowed.

Why fixed payments clear cards faster than minimums

The minimum payment a card issuer requires is recalculated each month against the falling balance, so as the balance shrinks the minimum shrinks in proportion. A fixed monthly payment behaves differently: the principal-reduction component grows as the balance falls, because interest takes a smaller share of each payment. Once the balance is small enough that interest barely matters, the payment becomes almost pure principal reduction. That is why even modest fixed payments shorten the payoff dramatically compared with percentage-of-balance minimums, which is the contrast this calculator makes visible.

How payment size moves the answer

The relationship between monthly payment and months to payoff is not linear. On the defaults, doubling the payment from 250 to 500 cuts the term from 26 months to 12, and cuts total interest from 1,285.72 to 574.44, so the term falls by more than half and the interest by more than half again. At a zero rate the same doubling would take 20 months to exactly 10, an exact halving, and the advantage over that exact halving grows as the rate rises.

The mechanism compounds: faster paydown lowers the running balance, which lowers each subsequent interest charge, which leaves more of the next payment reducing the principal. Re-running the calculator at a few different payment amounts shows the curve directly.

How APR moves the answer

The same balance and the same payment produce very different total interest figures at different APRs. A small drop in rate, for example after a balance transfer to a lower-rate card or after a credit-profile improvement, can shorten the payoff and reduce total interest by amounts that look surprisingly large compared with the rate change itself. The calculator can be run at the original APR and a hypothetical lower one to see the gap directly. This is also why standardised rate disclosure exists: European consumer credit rules require lenders to quote an annual percentage rate that expresses the total cost of the credit, so competing offers can be compared on the same basis rather than on the monthly figure alone.

How balance transfers fit in

Moving a balance to a card with a lower or zero promotional rate changes both the rate the calculator should use and adds an upfront fee that needs to be factored into the comparison. The Balance Transfer Savings Calculator handles that two-stage comparison directly. For a fixed-rate card without a transfer, this calculator covers the case.

When the simulation refuses to run

If the monthly payment is at or below the monthly interest charge on the starting balance, the balance grows under those payments rather than shrinking, and there is no payoff date at all. The calculator detects this and returns an explicit error rather than reporting a misleading number. On the defaults the first month’s interest is 91.67, so any payment at or below that figure would fail this check. For a valid simulation the monthly payment must exceed the balance multiplied by the APR divided by 12.

Where the simulation simplifies

The calculation assumes a constant APR, no late fees, no new spending added during payoff, and a fixed monthly payment held constant from start to clear. Real card use adds new charges to the balance during payoff, real life sometimes leads to missed payments, and card issuers sometimes change the rate after one. The calculator covers the steady-state case, and actual account behaviour drifts from it under those conditions. Revolving credit balances are large enough in aggregate that central banks track them as a category, which is a reminder that the steady-state case is not the common one.

Where to look next

The Minimum Payment Trap Calculator handles the alternative scenario, paying only the minimum with that minimum recalculated each month from the current balance. The Debt Snowball vs Avalanche Calculator handles multi-card strategies and how to allocate a fixed total payment across several balances. For a single card at a fixed payment, this page is the right one.