Credit Card Interest Calculator
Quick answer
Approximate monthly interest ≈ (APR/12) × average daily balance for many issuers (simplified).
For a related estimate, see Apr Calculator.
Explore further: Auto Loan Calculator · Car Loan Calculator
Finance charge
Periodic rate times balance subject to finance charge—cards vary on timing and rounding.
Explore further: Credit Card Calculator · Credit Card Payoff Calculator
This intent isolates “how much interest this month” from average balance and APR—helpful for budgeting after a large purchase or balance transfer window ending. Use this when you are working from real inputs—quotes, listings, statements, or specs—not placeholder guesses alone.
How to use this calculator
- Average daily balance: Statements show how balance varied—rough average if unknown.
- Grace periods: Paid-in-full customers may owe $0 interest—model only revolve portions.
- Different APR buckets: Purchases vs cash advance rates differ—split balances if needed.
Real-world examples
- Example: $3,000 balance at 22% APR → ~$55 monthly interest at 1/12 simple split (illustrative).
- Sensitivity check: Nudge the rate by about +0.5% and the principal by about −5%. If the payment, break-even, or target amount moves enough to change your decision, you are still on a steep part of the curve where small inputs matter.
Explore further: Debt Avalanche Calculator
What this means
Average daily balance matters—large mid-cycle purchases can raise interest even if you pay some principal.
FAQ
Is this a loan commitment?
No. Outputs are educational estimates. Final payments, APR, and fees come from your lender’s disclosures.
How accurate is this calculator?
It applies standard math to the inputs you enter. Real lenders, payroll rules, and rounding can differ—use results for planning and comparison, not as binding quotes.
Why might my result differ from another website?
Different assumptions (APR vs note rate, day-count, tax year, rounding mode, or unit definitions) shift outputs slightly. Align inputs with the same definitions when you compare.