Multiple Credit Card Payoff Plan Calculator

A multiple credit card payoff plan calculator estimates how long it may take to repay several card balances using a chosen monthly payment for each account. Enter each balance, APR, and monthly payment to estimate the payoff time and interest by card, then compare the combined totals; the estimate assumes each payment stays fixed.

Formula

For each card, the estimated number of monthly payments is n = ceil(round(−ln(1 − r × B ÷ M) ÷ ln(1 + r), 6)), where r = APR ÷ 1200. The calculator rounds the computed month count up to a whole payment. This formula assumes the payment is greater than the first month’s interest; if it is not, the debt does not decline under the model.

• B is the card balance in dollars.
• APR is the annual percentage rate entered as a percentage, such as 24 for 24%.
• r is the monthly rate as a decimal.
• M is the fixed monthly payment in dollars.
• n is the estimated number of months until payoff.

The headline result is the larger of the two card payoff times: the estimated time until both are paid off if each card receives its entered payment. Combined payments are estimated as each monthly payment multiplied by that card’s payoff months. Estimated interest is those payments minus the starting balances. The formula uses a simplified fixed-payment model rather than calculating a different final, smaller payment.

Worked Example

Using the defaults, Card 1 has a $3,000 balance, 24% APR, and a $150 monthly payment. Card 2 has a $5,000 balance, 18% APR, and a $200 monthly payment.

1. Card 1 monthly rate: 24 ÷ 1200 = 0.02. Its estimated months are ceil(round(−ln(1 − 0.02 × 3000 ÷ 150) ÷ ln(1.02), 6)) = 25.
2. Card 2 monthly rate: 18 ÷ 1200 = 0.015. Its estimated months are ceil(round(−ln(1 − 0.015 × 5000 ÷ 200) ÷ ln(1.015), 6)) = 30.
3. Longest payoff time: max(25, 30) = 30 months.
4. Combined payments: ($150 × 25) + ($200 × 30) = $9,750.
5. Estimated interest: $9,750 − $3,000 − $5,000 = $1,750.

Assumptions

• The APR for each card remains fixed throughout the estimate.
• Payments are made monthly at the end of each period, with no missed or late payments.
• Interest compounds monthly at APR ÷ 12.
• The calculator excludes new purchases, fees, changing rates, promotional periods, and any lender-specific payment allocation or billing rules.

How to Use a Multiple-Card Payoff Plan

Enter each card’s current balance, annual APR, and the amount you expect to pay toward that card every month. Use the account’s current figures rather than the card’s limit or its minimum payment from an old statement. The calculator has two card entries to demonstrate the method; for more cards, calculate each account separately and add its payments and interest to the totals.

For a plan that directs a fixed total amount toward debt, first decide how that total is divided among the cards, then enter the resulting monthly payment per card. This calculator does not automatically shift a payment to another account when one card is paid off. If you plan to roll a paid-off card’s payment into another balance, the payoff schedule changes and requires a month-by-month calculation.

Choosing a Payoff Strategy

Two common ways to organize payments are the avalanche and snowball methods. In an avalanche approach, extra money is directed to the card with the highest APR while payments continue on the others. This focuses additional payments where the stated interest rate is highest, though the exact savings depend on balances, rates, fees, and payment timing. In a snowball approach, extra money goes to the smallest balance first; this changes the order of account payoffs, but does not by itself lower the interest charged on another balance.

Whatever the order, account minimums and due dates still matter. If an entered payment is below the interest accumulating under this simplified model, the formula cannot estimate a payoff; a balance may persist or grow. Check the current statement for payment requirements and contact the issuer if a payment is difficult to make. This calculator does not determine a required minimum.

What the Estimate Leaves Out

Credit card interest can depend on the balance used for billing, transaction dates, daily rate calculations, grace periods, and payment posting. Real accounts may also have variable APRs, promotional rates, annual or other fees, cash advances, new purchases, and different terms for different transaction types. A single APR and fixed monthly payment cannot represent every such detail.

The model also treats the same payment as continuing until the final estimated month. In practice, the last payment is often smaller than the regular payment because it only covers the remaining balance and accrued interest. Consequently, combined payments and interest are planning estimates, not statement-level quotes. Check issuer statements for the balance, current APR, applicable terms, and payment due date.

Frequently Asked Questions

Should I pay the highest-interest card first?
The avalanche method directs extra payments to the highest-APR balance while paying other accounts as required. It can reduce interest compared with directing the same extra amount to a lower-rate balance, all else being equal, but actual results depend on the account terms and payment schedule.

Does this calculator include minimum payments?
No. Enter the monthly amount you intend to pay on each card. The calculator does not look up an account’s required minimum or verify that an entered payment meets its terms.

Why does the calculator need APR and monthly payment?
The APR sets the model’s monthly interest rate, and the payment amount determines how quickly the balance falls after interest. A balance and APR alone are not enough to estimate a payoff date.

Can I use this for more than two credit cards?
Yes. Apply the same calculation to each additional card, then add its estimated payments and interest to the respective totals. The combined payoff time is the longest individual payoff time only if you keep the entered payments fixed and do not redirect payments after an account is cleared.

Why might my statement show a different payoff amount?
The estimate simplifies interest and assumes a constant APR and payment. Actual balances can reflect daily interest, new transactions, fees, variable rates, payment dates, and other terms not entered here.

This result is an estimate for education; the card issuer’s disclosures and account statements give the exact figures.

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in b1 | Card 1 balance | $ | 3000 | 0 | 100000000
in a1 | Card 1 APR | % | 24 | 0.01 | 100
in m1 | Card 1 monthly payment | $ | 150 | 0.01 | 100000000
in b2 | Card 2 balance | $ | 5000 | 0 | 100000000
in a2 | Card 2 APR | % | 18 | 0.01 | 100
in m2 | Card 2 monthly payment | $ | 200 | 0.01 | 100000000
out months | Longest payoff time | months | max(ceil(round(-ln(1 - a1 / 1200 * b1 / m1) / ln(1 + a1 / 1200), 6)), ceil(round(-ln(1 - a2 / 1200 * b2 / m2) / ln(1 + a2 / 1200), 6))) | 0
out total | Combined payments | $ | m1 * ceil(round(-ln(1 - a1 / 1200 * b1 / m1) / ln(1 + a1 / 1200), 6)) + m2 * ceil(round(-ln(1 - a2 / 1200 * b2 / m2) / ln(1 + a2 / 1200), 6)) | 2
out interest | Estimated total interest | $ | total - b1 - b2 | 2