Credit card interest calculator
Most cards charge a daily rate on the average daily balance. Enter the figures from your statement to see the cycle interest.
Loading the tool…
Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter average daily balance, annual interest rate (apr) and days in billing cycle.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Daily rate = APR ÷ 365. Cycle interest = average daily balance × daily rate × days in the cycle.
Example
Inputs: Average daily balance = 2,000, Annual interest rate (APR) = 24 %, Days in billing cycle = 30 days. Result: Interest for the cycle: 39.45; Daily periodic rate: 0.065753%; Balance plus interest: 2,039.45.
Limits and caveats
- Uses a 365-day year; some banks use 360.
- Ignores the grace period: paying the full statement on time usually means no interest on purchases.
Questions about this tool
What is the average daily balance?
The sum of each day-end balance in the cycle divided by the number of days. Statements often show it.
Why does interest change month to month on the same balance?
Cycles run from 28 to 31 days and interest accrues daily.
Is the APR the monthly rate?
No. The APR is yearly; the monthly rate is about APR ÷ 12 and the daily rate is APR ÷ 365.