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Credit Card Interest Calculator

Monthly and daily interest charged on a credit card balance from the APR, using the average daily balance method.

Enter values

Results update as you type.

Result

Interest this cycle

$45.00

Daily periodic rate
0.06%
Interest per year (if unchanged)
$547.50
Effective annual rate (daily compounding)
24.47%

About the Credit Card Interest Calculator

Monthly and daily interest charged on a credit card balance from the APR, using the average daily balance method.

Also known as: credit card interest, apr to monthly interest, daily periodic rate, apr cost calculator.

How to use this calculator

  1. Enter average daily balance, apr, days in billing cycle.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

Interest = balance × (APR ÷ 365) × days

Worked example

Using the values pre-filled in the calculator above:

  • Average daily balance = 2,500
  • APR = 21.9 %
  • Days in billing cycle = 30

the calculator returns:

  • Interest this cycle: 45
  • Daily periodic rate: 0.06%
  • Interest per year (if unchanged): 547.5
  • Effective annual rate (daily compounding): 24.47%