See how much interest your credit card balance costs you each month and year. Understand the true cost of carrying a balance with your current APR.
Credit card interest compounds daily, which means your balance grows faster than most people realize. Understanding how your APR translates into actual dollars of interest each month is essential for making smart decisions about balance transfers, paying down debt, or choosing between cards.
This credit card interest calculator reveals the monthly and annual cost of carrying a balance on your credit card. The methodology calculates the daily periodic rate by dividing your APR by 365, then multiplies it by your average daily balance to estimate monthly interest charges. It also shows how minimum payments are primarily applied to interest with only a small amount reducing principal. Understanding interest costs is essential because credit card debt is among the most expensive consumer debt, with rates averaging 20-25% APR. The calculator illustrates the "interest trap" where making only minimum payments keeps you in debt for decades. Real-world applications include understanding the true cost of a purchase when paying over time, motivating debt payoff by showing interest amounts in concrete dollar terms, and comparing the cost of making only minimum payments vs. paying a fixed amount. Limitations include not accounting for variable rates, new purchases during the billing cycle, and promotional 0% APR periods.
Result: A $5,000 credit card balance at 22% APR accrues approximately $91.67 in interest per month ($5,000 x 22% / 365 days x 30 days), or about $1,100 per year. If your minimum payment is 2% of balance ($100), only about $8.33 would reduce your principal while $91.67 goes to interest, meaning less than 9% of your payment actually pays down the debt.
Understanding how to use financial calculators effectively requires knowing the underlying concepts. The credit card interest involves several key financial principles that affect your results.
Our calculator uses industry-standard formulas verified by certified financial professionals. The inputs you provide are processed entirely in your browser — we never store or transmit your financial data. Results update in real time as you adjust values, allowing you to explore different scenarios quickly.
For the most accurate results, use current figures from your most recent financial statements. If you are unsure about a specific input, our default values represent national averages based on data from the Federal Reserve, IRS, and Bureau of Labor Statistics.
Remember that calculator results are estimates for educational purposes. Your actual financial situation may differ based on factors like your credit score, specific lender terms, local regulations, and market conditions. We recommend consulting with a qualified financial professional before making major financial decisions.
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Results are estimates only and not financial advice. Calculator logic verified by David Thompson, AFC®. Full disclaimer · Methodology