Credit Card Fixed Payment Payoff Calculator

Enter Calculation

Current Balance ($)

Annual Interest Rate (APR %)

Fixed Monthly Payment ($)

Results

Months to Pay Off

47

months (3.9 years)

Time in years	3.92
Total amount paid	$7,050
Total interest paid	$2,050

What This Calculator Does

The Credit Card Fixed Payment Payoff Calculator tells you how many months it will take to eliminate a credit card balance if you pay the same fixed amount every month. It also shows the total you will pay and how much of that is interest. This is useful for planning a debt-free date and for seeing how a higher monthly payment dramatically shortens the timeline.

A fixed monthly payment steadily reduces the balance to zero over n months.

How to Use It

Enter your current balance, the card's annual interest rate (APR), and the fixed amount you intend to pay each month. The calculator assumes interest compounds monthly and that you make no new purchases on the card. Press calculate to see the number of months (and years) until the balance hits zero, plus the total interest cost.

The Formula Explained

The payoff time is found with the loan-amortization equation:

$$n = \frac{-\ln\!\left(1 - \dfrac{r \cdot B}{P}\right)}{\ln(1 + r)}$$

Here r is the monthly interest rate (APR ÷ 12, as a decimal), B is the starting balance, and P is the fixed monthly payment. The result n is the number of months, rounded up to the next whole payment. Important: if your payment is less than or equal to the monthly interest (\(B \times r\)), the balance never shrinks and the card is never paid off — the calculator flags this.

Each fixed payment P covers the month's interest first, with the rest cutting the balance.

Worked Example

Suppose you owe $5,000 at 18% APR and pay $150 per month. The monthly rate is \(r = 0.18 / 12 = 0.015\). Then $$n = \frac{-\ln\!\left(1 - \dfrac{0.015 \times 5000}{150}\right)}{\ln(1.015)} = \frac{-\ln(0.5)}{\ln(1.015)} \approx \frac{0.6931}{0.014889} \approx 46.56,$$ rounded up to 47 months (about 3.9 years). Total paid \(\approx 47 \times \$150 = \$7{,}050\), of which about $2,050 is interest.

FAQ

Why is my payment "too low"? If your fixed payment doesn't exceed one month's interest, the balance grows or stays flat forever. Increase the payment above \(B \times (\text{APR}/12)\).

Does this include new purchases? No. It assumes you stop adding charges to the card.

Is the answer rounded? Yes — months are rounded up because you can't make a partial final payment, so the final month clears any small remaining balance.