Credit Card Interest Calculator — What Your Balance Really Costs
Carrying a balance has a price tag most people never compute. Enter your balance and APR to see the daily, monthly, and yearly cost of standing still — often the most motivating numbers in personal finance.
- Per day
- $4.27
- Per year
- $1,560.00
How this calculator works
- Card interest accrues daily: balance × APR ÷ 365, compounding as it's added to the balance. A $6,500 balance at 24% quietly costs about $4.27 every single day.
- Interest is only charged if you carry a balance — pay the statement in full by the due date and the grace period makes your APR irrelevant.
Frequently asked questions
Why did I pay interest after paying in full?
Trailing (residual) interest: charges accrued between the statement date and the day your payment arrived. Pay the 'payoff amount' from customer service, not the statement balance, when closing out a carried balance.
What's the average credit card APR?
Around 21–24% in 2026 for accounts assessed interest — and store cards often run 28–32%. Your rate is on your statement, and a call requesting a reduction succeeds more often than people expect.
Does interest hurt my credit score?
Interest itself doesn't, but the balance it grows does — higher utilization lowers scores, creating a feedback loop that makes carrying balances doubly expensive.
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Disclaimer: Results are estimates for educational purposes only and are not tax, legal, or financial advice. Tax rules are simplified (credits, phase-outs, and local taxes may not be modeled). Verify important decisions with the IRS, your state tax authority, or a licensed professional.