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Credit Card Interest Calculator

Estimate your credit card interest charges, payoff time, and total repayment based on your balance, APR, and monthly payment.

Your Details

Overview

Use this Credit Card Interest Calculator to estimate how much interest you may pay, how long repayment could take, and the total amount you might repay based on your balance, APR, monthly payment, fees, and new charges.

How it works

The calculator converts your APR into a monthly interest rate and estimates interest on your outstanding balance each month. It compares your monthly payment against interest, fees, and any new charges to estimate how much of your payment reduces the principal. For payoff time, it uses a standard fixed-payment amortization approach, which is most useful when your payment is higher than your monthly interest and other ongoing charges.

How to use this calculator

  1. 1Enter your current credit card balance.
  2. 2Add your card's APR as an annual percentage rate.
  3. 3Enter the monthly payment you plan to make.
  4. 4Include any monthly fee and expected new monthly charges if relevant.
  5. 5Review the estimated payoff time, first month interest, and total repayment.

Example Calculation

Current balance

$5,000

Annual percentage rate (APR)

23%

Monthly payment

$200

Monthly fee

$0

New monthly charges

$0

Estimated payoff time

34 months

With a $5,000 balance at 22.9% APR and a $200 monthly payment, the balance would typically take around 32 months to repay, with about $1,400 in total interest over the repayment period.

Frequently asked questions

What does this credit card interest calculator estimate?

It estimates your monthly interest, payoff time, total repayment, and the extra amount paid above your starting balance.

Why is my payoff time so long?

If your APR is high or your monthly payment is only slightly above the interest charged, the balance reduces slowly and repayment takes longer.

What happens if I keep adding new charges?

New monthly charges increase the amount you owe and can greatly extend payoff time or prevent the balance from falling.

Does this calculator include minimum payment rules?

No. It assumes you make the fixed monthly payment you enter rather than a changing card issuer minimum payment.

Will my real credit card interest match this exactly?

Not always. Card issuers may use different daily balance methods, compounding rules, fees, and promotional rates, so actual results can differ.

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Assumptions and warnings

Assumptions

  • The APR stays the same for the full repayment period.
  • Your monthly payment amount stays constant.
  • Interest is estimated using a monthly rate based on the APR you enter.
  • Results are estimates and do not include issuer-specific compounding methods, minimum payment rules, or promotional rates.
  • If you add new charges or monthly fees, they are assumed to stay the same each month.

Warnings

  • This calculator provides an estimate only and is not financial advice.
  • If your monthly payment is too low to cover interest, fees, and new charges, your balance may not decrease.
  • Credit card issuers may calculate interest differently, so actual charges can vary.