How to read the credit card payoff results
The calculator turns a balance, an interest rate and a payment plan into a month-by-month schedule, then reports four things: how long the balance takes to clear, how much interest you pay on the way, how much you pay in total and what the first payment is. With the default inputs, a 8,000.00 balance at 18% with a 200.00 monthly payment clears in 5 years 2 months, costing 4,308.95 in interest and 12,308.95 in total, with a smaller final payment of 108.95.
Read the tiles together. Time to pay off is the headline, but total interest is the cost of that time. The chart shows the balance falling while cumulative interest rises and flattens, which makes it easy to see how much of your early payments goes to interest rather than to the balance. The table below the chart lists every month so you can check any row by hand. If the plan does not repay the card, the page says so plainly and shows no payoff date, no lifetime interest claim and no savings figure, because those numbers would not mean anything.
Everything on this page is an estimate from an equal-month model. It is useful for comparing plans against each other, and it is not a forecast of what your issuer's statement will show.
Statement inputs and the minimum-payment policy
You need three numbers from your statement: the current balance, the annual percentage rate and the payment you intend to make. The rate is a nominal APR, which the model divides by twelve to get a monthly rate. If your card has several balances at different rates, such as purchases and a cash advance, enter the one you want to study, or run the tool once for each.
Minimum payments are the hard part, because no two issuers use exactly the same rule. The Consumer Financial Protection Bureau's published contract definitions say that the bill states the minimum amount you must pay by the due date, and that missing it can bring a late fee. The formula behind that number comes from your own card agreement. For that reason the two minimum-payment options here are editable samples. One takes a percentage of the opening balance, subject to a floor. The other takes the month's interest plus a percentage of the balance, again subject to a floor. Change the percentage and the floor until the first payment matches your statement, then read the rest of the schedule as a projection of that policy, not as a promise from the issuer.
You can also add an extra payment on top of whichever plan you choose, and an optional first payment date so the schedule shows calendar dates. Dates move forward one calendar month at a time, keeping the day of the month where it exists and falling back to the last day of shorter months.
Where to find each number: the balance and APR are in the summary section of your statement, and the minimum due sits beside the due date. If you have a promotional rate, run the card twice, once at the promotional rate for its remaining months and again at the standard rate for what is left, because the model holds one rate constant. Fees and new purchases are left out on purpose, so stop adding to the card while you test a plan.
Fixed payment versus a declining minimum
A fixed payment never changes. A minimum based on the balance shrinks as the balance shrinks, and that is where the trouble starts. Suppose the same 8,000.00 balance at 18% is paid with a minimum of 2% of the opening balance and a 25.00 floor. The first payment is 160.00, which looks affordable, but as the balance falls the required payment falls with it, and the card takes 38 years 8 months to clear. The interest bill is 21,328.33, which is 17,019.38 more than the 4,308.95 paid under the fixed 200.00 plan, even though the first payments are similar.
The second sample, interest plus 1% of the balance with the same floor, starts at 200.00 and clears in 22 years 5 months with 11,038.69 of interest. Because it always covers the month's interest and then chips away at principal, it is much faster than a pure percentage of the balance. The lesson is not that one sample is the right model for your card. It is that the design of the minimum matters more than its starting size, and that a declining minimum can keep a balance alive for decades.
A practical way to use this is to pay a fixed amount close to your first minimum payment instead of letting the payment decline. Enter your first minimum as a fixed payment and compare the two rows of the policy table. The fixed plan keeps the payment steady, so the balance clears far sooner and the interest bill is smaller, with no change to your monthly cash flow.
The floor is what keeps a percentage minimum from ever reaching zero. In the first sample it sets the payment to 25.00 in 92 of the 464 months, a large share of the schedule. After five years of payments the balance is still 5,922.09, so most of the cost arrives late, long after the first statement made the plan look cheap.
The interest-plus-principal sample behaves differently because its payment can never drop below the month's interest. That removes the trap of a balance that barely moves, and it is why the same card clears in 22 years 5 months instead of 38 years 8 months. If your issuer's minimum looks like either sample, the schedule shows what following only the minimum costs; if it looks like neither, change the floor and the percentage until the first payment matches your statement.
The payment formulas
The model works in whole cents. Each month it takes the opening balance B and the monthly rate r, which is the APR divided by 12. The interest is I = B × r, rounded half up to the cent. The policy payment depends on the plan you chose:
- Fixed: the payment you enter.
- Percentage minimum: the larger of the floor and the entered percentage of the opening balance.
- Interest plus percentage: the larger of the floor and (I plus the entered percentage of the opening balance).
Any extra payment is added to the policy payment. The actual payment is the policy payment plus extra, but never more than the balance plus that month's interest, so the final payment is smaller. The closing balance is the opening balance plus interest minus the payment, and the principal reduction is the payment minus the interest. Every row satisfies opening + interest − payment = closing, so you can verify any line with a calculator. Because cents are rounded each month, results can differ from a spreadsheet that carries unrounded interest by a few cents or occasionally by one payment.
Here is the first month of the default plan by hand. The monthly rate is 18% ÷ 12 = 1.5%, so interest on 8,000.00 is 120.00. The 200.00 payment leaves 80.00 for principal and a closing balance of 7,920.00. In month two the interest is 118.80 on 7,920.00, so principal rises to 81.20. Rounding to the cent is half up, so an interest figure that lands exactly halfway, such as 1.505, becomes 1.51 and never 1.50.
Because interest is always computed on the opening balance, the order of operations inside a month does not matter in this model: the interest is added, the payment is subtracted, and the result opens the next month.
Pay off by a deadline and the rounding rule
The deadline mode answers the question "what must I pay each month to be done in n months?" For a balance B, monthly rate r and n months the level payment is B × r ÷ (1 − (1 + r)^−n). At 0% interest it is simply B ÷ n. For 8,000.00 at 18% over 24 months the formula gives about 399.40, and the model reports 399.40 a month, with 1,585.43 of interest and a final payment of 399.23.
The payment is rounded up to the next cent, never down. Rounding down by even one cent leaves a small residual at month 24 that spills into a 25th month, and a plan advertised as a 24-month payoff would quietly become a 25-month one. The calculator checks its answer against the cent ledger and, if rounding would leave a residual, raises the payment by the smallest amount that clears the balance on time. It never adds a month and never reports the payment times the number of months as the total, since the final payment is smaller than the rest. A shorter deadline costs more each month and less in interest: 12 months needs 733.45 a month and costs 801.29 in interest, while 48 months needs 235.01 a month and costs 3,279.75.
At 0% interest the arithmetic is plain division, and it shows why rounding up matters. 8,000.00 over 24 months is 333.34 a month when rounded up, which leaves a final payment of only 333.18. Rounding down to 333.33 would leave a few cents unpaid at month 24. Interest changes the answer only slightly for short deadlines and a lot for long ones, so a longer target costs far more in interest than its monthly saving suggests.
Treat the deadline payment as a floor and not a ceiling. Paying more than it clears the card earlier and costs less interest.
Worked monthly ledger
Here are the first six months of the default plan. Interest is the opening balance times 1.5%, since 18% divided by 12 is 1.5%, rounded to the cent. The first payment of 200.00 covers 120.00 of interest and leaves only 80.00 for principal.
| Month | Opening | Interest | Payment | Closing |
|---|---|---|---|---|
| 1 | 8,000.00 | 120.00 | 200.00 | 7,920.00 |
| 2 | 7,920.00 | 118.80 | 200.00 | 7,838.80 |
| 3 | 7,838.80 | 117.58 | 200.00 | 7,756.38 |
| 4 | 7,756.38 | 116.35 | 200.00 | 7,672.73 |
| 5 | 7,672.73 | 115.09 | 200.00 | 7,587.82 |
| 6 | 7,587.82 | 113.82 | 200.00 | 7,501.64 |
Notice that the interest falls a little each month while the payment stays the same, so the principal part grows. By the end the balance reaches zero in month 62, where the final payment of 108.95 covers the last of the balance and one month of interest. Adding the interest column over all 62 months gives 4,308.95, and adding the payment column gives 12,308.95, which is the original 8,000.00 plus that interest. If these totals ever disagree on your own run, something has been typed incorrectly, and the page shows an error rather than a partial answer.
| Month | Opening | Interest | Payment | Closing |
|---|---|---|---|---|
| 60 | 495.37 | 7.43 | 200.00 | 302.80 |
| 61 | 302.80 | 4.54 | 200.00 | 107.34 |
| 62 | 107.34 | 1.61 | 108.95 | 0.00 |
The end of the schedule looks very different from the start. In month 1 only 40% of the payment is principal, because most of it pays the month's interest. In month 62 the principal share is 99%, because interest is charged on a balance that has almost gone. The mix flips as the balance shrinks.
This pattern, interest-heavy at first and principal-heavy at the end, is why extra money paid early is worth more than the same amount paid late: it removes balance that would otherwise be charged interest for many more months.
You can reproduce this table in a spreadsheet with three formulas: interest = ROUND(opening × APR ÷ 12, 2), payment = MIN(payment, opening + interest) and closing = opening + interest − payment. Copy the row down until the closing balance reaches zero, and the totals should match the page to the cent.
Why your statement will differ: daily balances and fees
This model charges one month of interest on the opening balance. Real cards usually work differently. The CFPB explains that many issuers calculate interest daily, using the average daily balance, and that the daily periodic rate is the rate charged per day. In the sample contract definitions it publishes, the daily periodic rate is the APR divided by 365, applied to the average daily balance and multiplied by the days in the billing cycle. A month with 31 days therefore costs slightly more interest than a month with 28, and a payment made early in the cycle lowers the average daily balance and the interest that follows.
Other differences are bigger than the day count. A grace period can make new purchases interest-free only if you pay the full balance each month, which is not the situation this tool studies. Fees, such as late fees and annual fees, change the balance. Promotional rates change the cost for as long as they last. Your statement may also split the balance into categories with different rates, and the CFPB notes that payments above the minimum generally go first to the balance with the highest rate. The calculator ignores all of these and holds the rate steady. Expect the schedule to be close in shape and total interest, not identical. Use it to compare plans against each other, and use your statement for the exact figure you owe.
Here is how large the difference can be in a simple case. At 18% APR the daily periodic rate under the CFPB sample definition is 18% ÷ 365, about 0.0493% a day. On an unchanged 8,000.00 balance, a 31-day cycle accrues about 122.30 of interest and a 28-day cycle about 110.47, against a flat 120.00 in this model. Over a year the two approaches land close together, but any single month can differ by a few dollars, and the payment date inside the cycle moves the figure further. That is a reason to treat the schedule as a plan for comparison and not as a promise of what each statement will show.
Extra-payment comparisons
Paying extra is the simplest way to cut the cost. On the default card, an extra 50.00 a month clears the balance in 3 years 8 months instead of 5 years 2 months, and the interest falls from 4,308.95 to 2,980.47, a saving of 1,328.48. An extra 100.00 a month clears it in 2 years 11 months and saves 2,015.52. Each extra dollar goes straight to principal, which lowers every later month's interest, so the savings grow faster than the payment does.
The page reports exact savings only when both plans actually repay the card. If the baseline plan never clears the balance, as when a payment barely covers interest, lifetime savings would depend on an end date that does not exist. In that case the page says the comparison cannot be stated exactly, instead of inventing a number from an incomplete schedule.
| Extra a month | Months | Total interest | Interest saved |
|---|---|---|---|
| None | 62 | 4,308.95 | 0.00 |
| 25.00 | 52 | 3,517.96 | 790.99 |
| 50.00 | 44 | 2,980.47 | 1,328.48 |
| 100.00 | 35 | 2,293.43 | 2,015.52 |
| 200.00 | 24 | 1,582.60 | 2,726.35 |
Each additional amount saves more in total, but the saving per extra dollar falls. The first 25.00 a month saves 790.99 of interest, while the step from 100.00 to 200.00 saves 710.83. The model cannot place one-off lump sums, so approximate a windfall by comparing a higher monthly figure.
A lump sum such as a tax refund works like a standing extra payment bunched into one month, and the earlier it arrives the more interest it saves.
Multiple debts and balance transfers
This tool models one card. If you owe several, the order in which you attack them matters, and the debt payoff calculator plans several debts together. If a lower-rate offer is available, the balance transfer calculator shows whether a transfer fee pays for itself. For a fixed-term loan that could replace the card balance, the loan payment calculator gives the monthly payment and total interest. Comparing the card's schedule here with a personal loan's schedule there is a quick way to see whether consolidating helps.
Two ideas help when more than one balance is involved. The avalanche method pays the highest-rate balance first and minimizes interest, and the snowball method pays the smallest balance first and trades some interest for early wins. For a transfer, compare the fee with the interest you would otherwise pay: a 3% fee on 8,000.00 is 240.00, while the first six months of the default plan cost 701.64 in interest, so a transfer can pay for itself quickly if the promotional period is long enough and you keep paying. Always check how long the offer lasts, what the rate becomes afterwards and whether new purchases are treated differently.
Assumptions and balances that never shrink
The model assumes no new purchases, no fees, a constant rate and no missed payments. It uses equal monthly periods, whole-cent rounding and the policy you entered. It does not model grace periods, promotional rates, penalty rates or issuer-specific minimum formulas.
Some inputs describe a balance that cannot be repaid. If the payment is no larger than the month's interest, the balance does not fall. At 1,000.00 with 24% APR and a 10.00 payment, the first month's interest is 20.00 and the balance after one month is 1,010.00, higher than where it started. The calculator stops and tells you there is no payoff under these assumptions, showing that first month, rather than letting the unpaid interest disappear. The opposite problem is a payment so small that repayment takes longer than the modeled 1,200 months: at 0% interest, a 5,000.00 balance paid 1.00 a month would still owe 3,800.00 after 1,200 months, so no payoff date is shown. A zero balance is reported as already cleared. At 0% interest the arithmetic is simple: 1,000.00 paid 100.00 a month takes 10 months and costs no interest.
Because everything is rounded to the cent every month, a schedule from a spreadsheet that carries unrounded interest can differ by a few cents. If your rate changes, re-run the page with the new rate and your current balance rather than extending an old schedule. Fees are not modeled, so add any late or annual fee to the balance you enter if you want it reflected.
Credit card payoff questions
Why does my minimum payment shrink every month?
If your issuer sets the minimum as a percentage of the balance, the minimum falls as the balance falls. That is why the plan takes so long. Paying a steady amount close to your first minimum clears the balance far sooner, because the payment no longer falls as the balance does.
What happens when my payment does not cover the interest?
The balance grows. The calculator stops and reports that there is no payoff under the assumptions, showing the first month's payment, interest and resulting balance. Raise the payment above the monthly interest to start repaying.
Why is the target payment only a model estimate?
The deadline result assumes a constant rate, equal months and no new charges, so the real payment that clears your card on time will depend on your issuer's daily interest calculation, fees and billing dates.
Why does my statement show a different balance or interest amount?
Issuers commonly use the average daily balance and a daily periodic rate, and they may add fees or apply payments to higher-rate balances first. This tool uses one month of interest on the opening balance, so small differences are normal. Compare the interest line on your statement with the first month here to see how far apart the two methods are for your card.
When should I use the multi-card debt payoff tool instead?
When you owe more than one card or loan and need to decide which to pay first, use the debt payoff calculator. This page is for a single card, where the question is the payment plan.
Sources: the Consumer Financial Protection Bureau explains how card interest is calculated and publishes credit card contract definitions. This page is for education and is not financial advice.