Free browser-based tool

Credit Card Interest Calculator

Calculate a billing cycle from APR and daily balances, compare payment dates, or estimate how long a fixed monthly payment would take to clear a balance.

By New Credit Cards Editorial DeskModels: billing cycle and monthly payoffPrivacy: inputs stay in this browserCurrency: U.S. dollars for display

Calculate one billing cycle

Use a known average daily balance, or follow a starting balance through two payment-date scenarios.

Does this balance bear interest? Purchase grace depends on your agreement and full-payment conditions. Cash advances and earlier accrued interest need separate treatment.

Which balance do you have?

Interest-bearing average daily balance

Use the average balance subject to this APR, not the closing or current balance.

APR for this balance

One fixed APR; 0% to 100%.

Days in the billing cycle

Use the actual length; 1 to 62 whole days.

Annual day-count basis Use the divisor in your account terms.

The starting figures are hypothetical. Entries stay in this page and are not sent to a server or saved after reload.

U.S. Bank: average daily balance calculation · CFPB: daily rate and annual divisor

Example: a $1,000 average daily balance

$19.73

Interest-bearing average daily balance of $1,000, 24% APR, 30 days and a 365-day basis.

$1,000 × (0.24 ÷ 365) × 30 = $19.73

This is our worked example. An average daily balance is different from a starting balance that grows with daily compounding.

Purchase grace, fees, multiple APRs and account-specific rounding can change the answer.

Longer-term planning

Estimate monthly payoff

This separate payoff model uses APR divided by 12, with one payment and one spending amount per month. The starting figures are a hypothetical example.

Estimated result

Payoff and interest

Adjust the hypothetical inputs, then select Calculate. Your full schedule will appear here.

Published method

How the monthly payoff estimate works

Every month uses the same disclosed approximation. The final payment is reduced to the amount actually needed.

monthly rate = APR / 100 / 12 interest = opening balance x monthly rate amount before payment = opening balance + interest + new spending payment = smaller of planned payment or amount before payment closing balance = amount before payment - payment

The model repeats until the balance reaches $0 or 1,200 months. It warns after month one if interest plus new spending prevents the balance from falling. It also reruns the same scenario with a payment $50 higher so you can compare interest and duration.

Read before relying

Monthly payoff assumptions and limits

This is an educational planning model, not an issuer statement calculation or payoff quote.

ApproximationAPR divided by 12

This payoff estimate uses monthly capitalization. Use the billing-cycle calculator to inspect daily balances and compounding over one cycle.

Simplified timingOne payment and spend amount

It does not place individual purchases, payments, fees, or credits on exact calendar dates.

Agreement controlsNo fees or APR buckets

Cash advances, transfers, promotions, fees, daily or issuer-specific compounding, and payment allocation can require separate modeling. This calculator uses monthly capitalization.

Grace periodInterest is assumed

This payoff model assumes its balance bears interest. A 0% APR models no interest at that rate; it does not establish purchase-grace eligibility or model deferred-interest terms.

Need an exact payoff?Contact the issuer through a verified channel. Interest may continue between a statement date and the day a payment is received, creating residual or trailing interest.

Learn the underlying rules

Sources and next steps

[1]Consumer Financial Protection Bureau, How does my credit card company calculate interest?
[2]CFPB, Credit card agreement database for issuer-submitted general terms.