Credit Card Interest Calculator
Calculate your real credit card interest charges, payoff timelines, and compare fixed monthly payments against the minimum payment debt trap.
Payment Breakdown (Principal vs. Interest)
Payoff Months
n = −ln(1 − (P × r) / M) ÷ ln(1 + r)With
P = $5,000.00, Monthly Rate r = 18.00% ÷ 12 = 0.015, Payment M = $250.00:First month interest =
$5,000 × 0.015 = $75.00. Principal reduction = $250 − $75 = $175.00.Calculated duration = 24 monthly cycles (Total Interest: $989.17).
Credit Card Repayment Schedule
| Period | Total Payments | Principal Paid | Interest Paid | Ending Balance |
|---|---|---|---|---|
| Year 1 (Mos 1–12) | $3,000.00 | $2,282.19 | $717.81 | $2,717.81 |
| Year 2 (Mos 13–24) | $2,989.17 | $2,717.81 | $271.36 | $0.00 |
| Total (24 Mos) | $5,989.17 | $5,000.00 | $989.17 | $0.00 |
About This Calculator
The Credit Card Interest Calculator empowers cardholders to understand the true cost of revolving debt. Credit cards operate on compound interest using an Annual Percentage Rate (APR). Every month you carry an unpaid balance, interest is assessed and added to your balance, reducing how much of your payment actually chips away at your principal.
This calculator provides dual calculation models: Fixed Payment Mode allows you to specify a set dollar amount each month to discover your exact debt-free date and total finance charges. Target Payoff Mode calculates the exact monthly payment required to become debt-free within a designated timeframe (e.g., 12, 24, or 36 months).
Payoff Formulas & Illustrative Example
Credit card interest compounds periodically. For any billing cycle, the periodic monthly interest rate is computed as:
r = APR ÷ 12
To determine the number of billing cycles (n) needed to pay off a balance (P) with a fixed monthly payment (M):
n = −ln(1 − (P × r) ÷ M) ÷ ln(1 + r)
Conversely, to calculate the required monthly payment (M) to eliminate a balance within n months:
M = (P × r × (1 + r)n) ÷ ((1 + r)n − 1)
Illustrative Worked Example:
Suppose you owe $5,000.00 on a credit card charging 18.00% APR, and you decide to pay a fixed $250.00 each month:
- Monthly Rate:
r = 0.18 ÷ 12 = 0.015(1.50% per month). - Month 1 Interest:
$5,000.00 × 0.015 = $75.00. - Month 1 Principal:
$250.00 − $75.00 = $175.00. New balance is$5,000.00 − $175.00 = $4,825.00. - Month 2 Interest:
$4,825.00 × 0.015 = $72.38. Principal reduction is$250.00 − $72.38 = $177.62. New balance is$4,647.38. - Outcome: After 24 cycles, the entire $5,000 debt is eliminated. You will have paid $989.17 in total interest and $5,989.17 in total repayments, with a final adjusted payment of $239.17.
How to Use This Calculator
- Select Your Goal: Choose Fixed Payment Plan if you know what you can afford each month, or Target Payoff Goal to see what payment is required to be debt-free by a specific date.
- Enter Your Credit Card Details: Input your current statement balance and your card's annual purchase APR.
- Set Your Repayment Parameters: Adjust the monthly payment slider or enter your target months.
- Analyze Your Savings: Review the signature result bar, cost breakdown, and visual donut chart to discover how much interest and time you save compared to paying the minimum.
Standard Payoff Benchmarks ($5,000 Balance at 18.00% APR)
The table below demonstrates how even modest increases in your monthly payment dramatically crush interest charges and accelerate your debt-free date:
| Monthly Payment | Payoff Time | Total Interest | Total Repayment | Interest Savings vs Min |
|---|---|---|---|---|
| Minimum Only (~$125) | ~188 Months (15.7 Yrs) | ~$4,215.00 | ~$9,215.00 | Baseline ($0) |
| $150.00 / month | 48 Months (4.0 Yrs) | $2,074.88 | $7,074.88 | Save $2,140+ |
| $200.00 / month | 32 Months (2.7 Yrs) | $1,315.65 | $6,315.65 | Save $2,899+ |
| $250.00 / month (Default) | 24 Months (2.0 Yrs) | $989.17 | $5,989.17 | Save $3,225+ |
| $350.00 / month | 16 Months (1.3 Yrs) | $663.78 | $5,663.78 | Save $3,551+ |
| $500.00 / month | 11 Months (0.9 Yrs) | $444.60 | $5,444.60 | Save $3,770+ |
Why Use a Credit Card Payoff Calculator?
Credit card statements are deliberately engineered around the "minimum payment" design, which covers only accrued interest plus a negligible slice (1% to 2%) of principal. By using an independent, mathematical payoff calculator, you gain three critical advantages:
- Escape the Minimum Payment Trap: Understand exactly how paying the bare minimum extends a \$5,000 purchase into a 15-year financial burden.
- Budget with Certainty: Pinpoint the exact dollar payment required to coincide with life milestones, balance transfers, or promotional 0% APR expiration dates.
- Accelerate Credit Score Improvement: Rapid principal paydown quickly lowers your credit utilization ratio (amounts owed), which accounts for 30% of your FICO score.