Credit Card Payoff Calculator
Find out exactly how many months it will take to pay off your credit card balance at a fixed monthly payment, and how much total interest you will pay. Use it before setting a payoff goal or negotiating a balance transfer.
About this calculator
This calculator uses the standard loan amortization payoff formula to determine the number of monthly payments needed to retire a credit card balance: months = CEIL(−log(1 − (balance × monthlyRate) / payment) / log(1 + monthlyRate)), where monthlyRate = APR / 100 / 12. The formula is derived by solving the present-value-of-annuity equation for n (number of periods). A critical constraint is that the monthly payment must exceed the interest accrued in the first month (balance × monthlyRate); otherwise the balance grows and payoff is impossible. Total interest paid = (months × monthlyPayment) − cardBalance. Knowing this figure motivates larger payments: doubling the payment typically more than halves the repayment period due to reduced compounding.
How to use
Assume a credit card balance of $4,500, an APR of 21%, and a monthly payment of $150. Monthly rate = 21 / 100 / 12 = 0.0175. Check feasibility: $4,500 × 0.0175 = $78.75 in monthly interest, which is less than $150—payment is sufficient. Apply the formula: months = CEIL(−log(1 − (4,500 × 0.0175) / 150) / log(1 + 0.0175)) = CEIL(−log(1 − 78.75 / 150) / log(1.0175)) = CEIL(−log(0.475) / 0.01735) = CEIL(0.7435 / 0.01735) = CEIL(42.85) = 43 months. Total interest = (43 × $150) − $4,500 = $6,450 − $4,500 = $1,950.
Frequently asked questions
How much faster will I pay off my credit card if I increase my monthly payment?
Increasing your monthly payment has a disproportionately large effect on payoff time because every extra dollar reduces principal faster, which in turn reduces the interest charged the following month. For example, on a $4,500 balance at 21% APR, paying $150/month takes about 43 months; increasing to $250/month reduces that to roughly 22 months—nearly half the time for only a 67% increase in payment. The interest savings are even more dramatic: the higher payment scenario saves hundreds of dollars in cumulative interest. Even small extra payments—$20 or $30 more per month—make a meaningful difference when sustained over time.
What is the minimum monthly payment needed to pay off a credit card balance?
The absolute minimum payment that will ever result in payoff is any amount greater than the interest accrued in a single month, calculated as balance × (APR / 12 / 100). Any payment at or below this threshold means the balance either stays flat or grows each month, and the debt is never eliminated. In practice, to pay off in a reasonable timeframe you need to pay significantly more than the minimum. A common rule of thumb is to pay at least 3–4% of your balance each month as a self-imposed minimum, rather than relying on the issuer's 1–2% minimum which leaves balances outstanding for decades.
Why does a small difference in APR have such a big impact on credit card payoff time?
Because credit card interest compounds monthly on the remaining balance, even a 2–3 percentage point difference in APR translates into substantially different interest charges accumulating month after month. On a $5,000 balance paid at $150/month, the difference between an 18% APR and a 24% APR is not just a fixed amount—it changes how quickly the principal decreases, which alters every subsequent month's interest calculation. Over a multi-year payoff period these small monthly differences compound into hundreds of dollars in extra interest and several additional months of payments. This is why balance transfer offers with lower promotional APRs can be so valuable when used strategically.