Credit Card Interest Calculator
Estimate a billing-cycle interest charge from the average daily balance, APR and day-count basis.
Formula
Interest = average daily balance × APR/100 × days / basis
Interest charge (money) ≈ (1,000)×(24)÷100÷365×(30)
How to use
- Enter the average daily balance subject to interest.
- Set APR, cycle days and the issuer’s 360/365-day basis.
- Read the estimated interest charge.
Examples
- Average balance 1,000 at 36.5%, 30/365 days: interest 30.
Frequently asked questions
Which balance should I enter?
Use the average of daily balances, not just the opening or statement balance.
Does this include daily compounding?
Only if it is already reflected in the average daily balance you enter.
Are grace periods and fees included?
No. Use only balances subject to interest; fees and minimum interest charges are excluded.
Sources
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