Months and interest to clear a balance.
n = -ln(1 - (r × P) / M) / ln(1 + r)
Credit card interest compounds monthly. To find the number of months n needed to pay off a balance with fixed monthly payments, we use the standard loan amortization formula rearranged for the number of periods:
This formula assumes a fixed monthly payment greater than the monthly interest charge, no new charges are added to the card, and interest is compounded monthly (standard for most U.S. credit cards).
Monthly rate r = 21.99% ÷ 12 = 0.021990 ÷ 12 ≈ 0.018325 n = -ln(1 - (0.018325 × 4200) / 150) / ln(1 + 0.018325) = -ln(1 - (76.965 / 150)) / ln(1.018325) = -ln(1 - 0.51310) / ln(1.018325) = -ln(0.48690) / 0.018158 = -(-0.71936) / 0.018158 = 0.71936 / 0.018158 ≈ 39.62 months Round up → 40 monthly payments Total paid = 39 × $150 + final balance payment ≈ $5,850 (approximate) Total interest = $5,850 − $4,200 ≈ $1,650
Result: **40 months** (~3 years 4 months) to pay off the balance. Total interest paid ≈ **$1,650**.
With a $4,200 balance at 21.99% APR and a $150/month payment, you would be debt-free in about 40 months, paying roughly $1,650 in interest — nearly 39% of the original balance. Increasing that monthly payment to just $200 would cut payoff time to about 27 months and save approximately $500 in interest. This illustrates why paying more than the minimum makes a significant financial difference.
Credit cards charge compound interest, meaning interest is calculated on your outstanding balance each month. Most U.S. issuers use the Average Daily Balance method, but for payoff planning purposes, the monthly compounding approximation used here is standard and widely accepted.
Credit card minimum payments are typically set at 1–2% of your balance or a small flat dollar amount. Because these payments barely cover the monthly interest charge, they can extend a $3,000 balance into 10+ years of payments and cost thousands in interest. For example, paying only the 2% minimum on a $3,000 balance at 20% APR could take over 17 years to pay off.
APR (Annual Percentage Rate) is the yearly cost of borrowing. For monthly compounding, the effective monthly rate is APR ÷ 12. A difference of even 5 percentage points in APR can add hundreds of dollars in interest on a typical balance. Always check whether your card has a variable APR, which can change with the federal funds rate.
Disclaimer: Results from this calculator are estimates for educational and planning purposes only. Actual payoff timelines and interest charges may differ based on your card issuer's billing cycle, fee structure, minimum payment policies, and any new charges added to the account. Consult your card issuer or a certified financial planner for personalized advice.
The total interest depends on your balance, APR, and how your issuer calculates the minimum. On a $5,000 balance at 20% APR with a 2% minimum payment, you could pay well over $6,000 in total interest over many years. Use this calculator with your actual minimum payment amount to see your specific scenario.
Generally, if your credit card APR (often 18–28%) exceeds your expected investment return (historically ~7–10% annually for diversified stock portfolios), paying off the debt first provides a guaranteed 'return' equal to your interest rate saved. This is a personal finance decision that may warrant advice from a financial planner.
For most credit cards, APR and the interest rate are essentially the same, since credit cards typically don't have origination fees baked into the rate the way mortgages do. However, APR is the more comprehensive and legally required disclosure figure. Always use the APR when calculating interest.
Yes, generally. Paying down your balance reduces your **credit utilization ratio** (balance ÷ credit limit), which is one of the most influential factors in your FICO score. Keeping utilization below 30% — and ideally below 10% — is recommended for the best score impact.
Enter the APR that applies to your current balance. Most cards list a 'Purchase APR' on your monthly statement. If you have cash advance balances or promotional rates, consider running separate calculations for each portion of the balance.
You can enter your minimum payment amount, but be aware the result may show a very long payoff timeline — sometimes decades. The calculator will still give you an accurate estimate, which can be motivating to find ways to pay even a little more each month.
The calculator uses monthly compounding (APR ÷ 12), which is the standard method for payoff planning and matches how most U.S. card issuers present rates. If your issuer uses daily compounding, actual interest may be marginally higher, but the difference is small for planning purposes.
Yes — use the reverse calculation mode. Enter your balance, APR, and desired number of months, and the calculator will output the required fixed monthly payment to hit that goal.
Because a larger fraction of each payment goes toward principal instead of interest when you pay more. This reduces the balance faster, which reduces next month's interest charge, creating a compounding benefit in your favor. Even $25–$50 more per month can cut months or years off your payoff timeline.
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