Credit Card Minimum Payment Calculator
How it works
Each month, interest accrues on the current balance (balance · annualRate / 12), and the payment due is whichever is larger: the minimum payment percentage of the balance, or the flat-dollar floor — 2% of the balance or $25, whichever is greater, is a common real-world formula. That payment is subtracted after interest is added, and the cycle repeats until the balance reaches zero or 600 months (50 years) pass, whichever comes first.
The optional fixed payment runs the same simulation with one change: instead of a payment that shrinks alongside the balance, it stays constant every month. Comparing the two side by side is the point of this tool — the minimum-payment path is what happens by default if nothing changes, and the fixed-payment path is what a bigger, steady payment buys back in time and interest.
Frequently asked questions
What is the "minimum payment trap"?
A minimum payment is usually a percentage of the balance (2% is common), so as the balance shrinks, the required payment shrinks right along with it. Interest, meanwhile, is charged on whatever balance remains, so the two can end up barely outpacing each other for years. The result is a card that always looks like it is "being paid down" every month while total time and total interest quietly balloon — often into years and into interest that dwarfs the original balance.
Why is there a 600-month cap, and what does the error actually mean?
600 months is 50 years — long past any reasonable payoff horizon. If the simulation is still not finished by then, it genuinely never finishes: whenever the minimum payment percentage is low enough relative to the interest rate, the required payment can fail to outpace the interest building up, and the balance creeps upward instead of down, forever. The error is that finding, stated plainly, not a bug — it means paying only the stated minimum (percentage or floor, whichever is greater) would not actually clear this balance at this rate.
How is this different from the Debt Payoff Calculator?
The Debt Payoff Calculator optimizes the order to clear several debts at once under a fixed extra monthly payment — snowball or avalanche, redirecting each cleared debt's minimum onto the next. This tool is about a single card, and it isn't optimizing anything: it exists to show what happens if you pay only the minimum on it, and to contrast that against a bigger fixed payment, so the cost of "just the minimum" is visible before you commit to it.