How to use the credit card interest calculator
- Enter your Card balance — the amount you currently owe on the card.
- Enter the Annual APR — the yearly interest rate shown on your statement.
- Read the result. Monthly, daily and annual interest all update as you type.
Worked example
A $5,000 balance at 22.9% APR costs about $95.42 a month in interest, or roughly $3.14 every day. Over a full year that is about $1,145 in interest if the balance stays the same.
The formula
Monthly interest = Balance × APR ÷ 12
Daily interest = Balance × APR ÷ 365 · Annual = Balance × APR
The APR is divided by 12 for a monthly figure and by 365 for a daily one. Credit cards quote APR as a yearly rate, so the monthly charge is always the annual rate divided by twelve.
What this number does and does not tell you
This estimate assumes the balance stays fixed and uses simple (non-compounding) interest for a quick read. Real cards usually compound daily and charge on your average daily balance, so the actual cost can be a little higher.
- Minimum payments barely dent the balance. Paying only the minimum can leave you paying interest for years while the principal barely moves.
- APR is not the same as the interest you pay. APR is the yearly rate; the interest you actually pay depends on your balance, how long you carry it, and whether you pay in full each month.
- Paying in full avoids interest. Most cards give a grace period — pay the statement balance before the due date and you pay no interest at all.