Estimate how long it will take to pay off your credit card and how much interest you will pay. Add extra payments, a one-time lump sum, or a minimum-payment rule.
How to use this calculator
- Enter your “Current balance” (the total you owe on the card right now).
- Enter the “Interest rate (APR)” (APR means annual percentage rate, the yearly interest rate as a percent).
- Enter your “Monthly payment” (how much you plan to pay each month).
- If you want to model a more realistic plan, open “Advanced options”:
- “Extra payment each month” adds a fixed extra amount on top of your normal payment.
- “One-time extra payment (month 1)” is a lump payment you make once at the start.
- “New spending added each month” is how much you keep charging to the card each month (this makes payoff slower).
- If you want to model how many cards work by default, turn on “Use a minimum payment rule instead”.
Then set:
- “Minimum payment percent of balance” (example: 2% means you pay 2% of whatever the balance is that month).
- “Minimum payment floor” (a smallest payment amount, like $35, even if the percent is lower).
- If you want an estimated payoff month, set “Start month” (optional).
- If your payoff might take a long time, use “Max months to simulate” (this stops the math after a limit so it does not run forever).
- Press “Calculate”. Check:
- “Time to payoff” (how long until the balance reaches $0).
- “Total interest paid” (the extra money paid for borrowing).
- The chart (how the balance drops over time).
Reality check: many credit cards calculate interest daily, and your due date, fees, and promos can change things. Treat this as a planning estimate.
Definitions
- Balance: how much you owe right now.
- Interest: the extra cost you pay for borrowing money.
- APR: annual percentage rate (yearly interest rate as a percent).
- Minimum payment: the smallest payment your card lets you make each month.
- Minimum payment percent: a rule like “pay 2% of the balance each month”.
- Minimum payment floor: a rule like “but never less than $35”.
- New spending: new charges you keep adding to the card each month.
- Payoff: when the balance reaches $0.
This is a month-by-month payoff simulation. It starts from your current balance, then repeats the same steps each month until the balance reaches $0 (or the max months limit is hit).
The calculator converts APR to a monthly rate using r = (APR / 100) / 12, then estimates monthly interest as interest = balance * r.
Many cards compute interest using a daily periodic rate and an “average daily balance” method, which can produce slightly different results than a simple monthly estimate.
- Optional new spending is added to the balance for the month.
- Interest for the month is estimated from the updated balance.
-
The payment for the month is chosen:
- If the minimum-payment rule is off: payment = your monthly payment + extra monthly payment (+ one-time extra in month 1).
- If the minimum-payment rule is on: payment = max(min percent of balance, min dollar floor) + extra monthly payment (+ one-time extra in month 1).
- Principal paid = payment – interest. If principal paid is not positive, the balance will not go down (the calculator stops and shows an error).
- If the payment is bigger than the remaining balance plus interest, the last payment is capped to exactly pay the balance off.
If you enter a start month, the payoff month is that start month plus the number of months the simulation took. This is a calendar estimate only. It does not know your statement cycle dates.
- Single APR only. Many cards have different APRs for purchases, balance transfers, and cash advances. Payment allocation rules can also differ when multiple APR buckets exist.
- No fees. Late fees, annual fees, and interest minimums are not modeled.
- Minimum payment is simplified. Real minimum payments often include interest and fees, and issuer formulas vary.
- New spending is treated as if it accrues a full month of interest in the model. Some accounts have a grace period for new purchases, but grace periods often do not apply when you are carrying a balance.