Numbers from this site's public API on a 4-card $15,000 portfolio at 17-24% APR. Open the calculator with your own balances and rates and the same numbers come out in real time.
The example portfolio
$15,000 is the size where the minimum payments alone come to $400 a month. This page uses four US credit cards — the same four-card shape and the same 24 / 21 / 19 / 17 APR set as the $15K in 1 year and $15K in 6 months case studies. Card A carries $6,000 at 24% APR with a $150 minimum; Card B $4,000 at 21% with a $100 minimum; Card C $3,000 at 19% with an $80 minimum; Card D $2,000 at 17% with a $70 minimum. The four minimums add up to $400 a month. Card A and Card B pay exactly 2.5% of their balance; Card C pays 2.667% and Card D 3.5%, so the two smallest cards are the ones paying themselves down hardest.
Weighted by balance, the portfolio's rate is 21.267% a year: $6,000 × 24%, $4,000 × 21%, $3,000 × 19% and $2,000 × 17% come to $3,190.00 of annual interest on a $15,000 balance. One twelfth of that is 1.77222%, which on the opening balance is $265.83 for the first month — $120.00 on Card A, $70.00 on Card B, $47.50 on Card C and $28.33 on Card D.
To clear all four in twenty-four months, the snowball method needs $916 a month, which is $516 above the minimums. Avalanche needs less — $858 — because it goes straight at the 24% card. Every figure on this page is for the snowball plan unless it says otherwise.
What the plan charges each card, in its own minimum
The four cards start at very different sizes, so comparing their interest bills in dollars mostly compares their balances. Counting each card's bill in its own minimum payment takes the size out of it and leaves the thing that actually varies: how many months the plan lets that card live.
Card D is the plan's first target. It is paid $586 a month — the $516 of new money plus its own $70 minimum — and it is gone in month 4. Four payments, and across the whole two years it is charged $65.48. Card D's own minimum is $70, so the entire twenty-four months costs it 0.94 of a single minimum payment. Its balance runs $2,000, then $1,442.33, $876.77 and $303.19, and then it is zero.
Card C is next. It gets the same $596 a month and dies in month 9, charged $302.51 — 3.78 of its $80 minimum. Card B takes the money from month 10 and finishes in month 15, charged $821.54, which is 8.22 of its $100 minimum. Card A is last in the snowball order: it pays its own $150 minimum for the first fourteen months, picks up $200.47 in month 15 when Card B closes, and then takes every payment from month 16 to month 24. It is charged $2,288.11 — 15.25 of its $150 minimum. The other three cards are all gone by then: Card A enters month 16 at $5,430.73, and the last nine payments of the plan send $5,987.64 at that one card.
Card A's balance is exactly three times Card D's. Its bill on the plan is 34.94 times Card D's. Nothing about the two cards changed between those two facts; what changed is that one of them was allowed to run for twenty-four months and the other for four.
| The card | Its minimum | Charged by the plan | In its own minimums |
|---|---|---|---|
| Card D — $2,000 at 17% | $70 | $65.48 | 0.94 |
| Card C — $3,000 at 19% | $80 | $302.51 | 3.78 |
| Card B — $4,000 at 21% | $100 | $821.54 | 8.22 |
| Card A — $6,000 at 24% | $150 | $2,288.11 | 15.25 |
The last column is the one to read against the second. The four minimums run from $70 to $150 — a spread of 2.14 times. What the plan charges them runs from 0.94 to 15.25 minimums — a spread of 16.3 times. The minimums are a size; the plan is a deadline, and a deadline is not proportional to size.
What the two years cost
The twenty-four months cost $3,477.64 of interest, and the total that leaves your account is $18,477.64. The interest is 23.18% of the balance you started with and 18.82% of everything you send. The whole two years of interest is 8.694 of the $400 minimum payments, and the monthly charge falls from $265.83 in month 1 to $12.93 in month 24 — 20.56 times less. By the last payment, 98.04% of the $659.64 reaches principal and only 1.96% is interest, against 29.02% in month 1.
Avalanche is cheaper here, and it is also faster. Run at the same $916 a month it is charged $2,844.18 — $633.46 less, so the snowball bill is 1.223 times the avalanche bill — and it lands in twenty-two months, two short of the plan. Avalanche can clear the balance at its own lower threshold of $858, and at that smaller payment it is charged $3,097.75; the $2,844.18 above is the equal-payment figure, so the two numbers differ by the payment they are measured at, not by the method.
The payments step down three times as cards close: $916 in months 1 to 4, $846 in months 5 to 9, $766 in months 10 to 15, $666 in months 16 to 23, and $659.64 in month 24. Each drop is exactly the minimum of the card that just cleared — $70 for Card D, $80 for Card C, $100 for Card B — and the fourth drop, Card A's $150, never arrives: the plan ends at $659.64 instead of $666. The balance path is $14,349.83, $13,690.13, $13,020.74, $12,341.53, $11,721.88, $11,092.23, $10,452.43, $9,802.29, $9,141.66, $8,549.91, $7,947.71, $7,334.88, $6,711.24, $6,076.58, $5,430.73, $4,873.34, $4,304.81, $3,724.90, $3,133.40, $2,530.07, $1,914.67, $1,286.97, $646.71 and zero.
The deadline itself is exact. $916 a month lands the payoff in twenty-four months; $915 adds a twenty-fifth and takes the interest to $3,484.06. Avalanche's own deadline sits lower: $858 finishes in twenty-four months, and $857 pushes it to twenty-five and $3,103.40. The first twelve months send $10,192.00 and the last twelve $8,285.64 — 18.70% less — and they retire $7,665.12 against $7,334.88. Twenty-four flat payments of $916 would come to $21,984; the plan sends $18,477.64, so $3,506.36 of those flat payments never happens.
Where the $516 comes from
This is the part that decides whether the plan happens, so it is worth stating plainly: you need $516 a month above the $400 you already pay — 1.290 times the minimums — and over the twenty-four months the new money alone is $12,384, which is 82.56% of the balance. The plan pays 2.290 times the minimums and finishes the job in 24 months instead of 81 — 3.375 times faster.
Two comparisons make the size of the ask concrete. The plan's $18,477.64 is 70.33% of the $26,271.94 the minimums-only path costs, so you spend about two thirds of the money and save $7,794.30. And month 1 of the minimums is charged the same $265.83 the plan is, but of that $400 only $134.17 reaches principal — 33.54%, against 70.98% for the plan's first payment. Leave the minimums running for the same twenty-four months and you would send $9,600, of which $5,680.86 is interest — 59.18% of it — and you would still owe $11,080.86, 73.87% of the balance.
Stretching the same $15,000 across different deadlines is a separate trade, and it is worth naming. The lowest payment that clears it in six months is $2,795 a month, for $977.62 of interest; in twelve months it is $1,540 a month, for $1,818.86; in twenty-four months it is $916 a month, for $3,477.64; in thirty-six months it is $700 a month, for $5,112.15. Going from one year to two cuts the payment by $624 a month and adds $1,658.78 of interest, which is 91.2% of the twelve-month bill. You are buying cash flow, and you are paying for it in interest.
Card by card, the minimums-only path is charged $6,180.29 on Card A, $2,925.88 on Card B, $1,584.15 on Card C and $581.62 on Card D, and it runs 81 months — Card D clears in month 37, Card C in month 58, Card B in month 69 and Card A in month 81. Avalanche on the same $400 takes the same 81 months and is charged $11,243.13, so on this portfolio the two methods are $28.81 apart when the payment is only the minimums.
Reproduce these numbers
Every figure on this page comes from this site's public API. Post the four balances, their rates, their minimums and extra: 516 to /api/payoff and you get the same months, the same $3,477.64 and the same per-card breakdown — including the remaining on each month of the timeline, once with extra: 516 and once with extra: 0. Two things that trip people up: APR goes in as a percentage (24, not 0.24), and extra is the amount above your total minimums, not your total payment — $516 here, which is what turns the $400 in minimums into $916 a month. Or just open the calculator and type your balances in — same engine, no payload.
If your target is a different size or a different deadline, the same analysis is in the $15K in 1 year, $15K in 6 months, $20K in 2 years, $20K in 1 year, $20K in 6 months, $25K in 2 years, $25K in 1 year, $30K in 2 years, $30K in 1 year, $30K in 6 months, $40K in 2 years, $40K in 1 year, $40K in 6 months, $80K in 2 years, $80K in 12 months, $80K in 6 months, $70K in 2 years, $70K in 12 months, $70K in 6 months, $60K in 2 years, $60K in 12 months, $60K in 6 months, $50K in 2 years, $50K in 12 months, $50K in 6 months, $10K, $10K in 6 months, $5K in 1 year, $5K in 6 months and $100K case studies, plus a 36-second walkthrough of the $25K case on YouTube. Shorter answers to the most common payoff questions live in the payoff questions hub.
Frequently asked
How much do I have to pay a month to clear $15,000 in two years?
On the four-card example here, $916 a month clears the $15,000 in twenty-four months on the snowball method, which is $516 above the $400 in minimums. Avalanche needs less — $858 — because it goes at the 24% card first.
How much interest does $15,000 cost over two years?
The snowball plan is charged $3,477.64 and the total that leaves your account is $18,477.64 — the $15,000 balance plus that interest. The interest is 23.18% of the balance you started with and 18.82% of everything you send, and it is 8.694 of the $400 minimum payments. Run at the same $916 a month, avalanche finishes in twenty-two months and is charged $2,844.18, which is $633.46 less.
What does it mean to count a card's interest in its own minimum payment?
It is a way of pricing the plan card by card. Divide what the plan charges a card over the whole twenty-four months by that card's own minimum, and the four cards come out at 0.94, 3.78, 8.22 and 15.25. Card D is charged $65.48 against its own $70 minimum, so the whole two years costs it less than a single one of its minimums. Card A is charged $2,288.11 against a $150 minimum — more than fifteen of them. The four minimums themselves only span 2.14 times, from $70 to $150, so the same unit shows what the deadline does: the cards are charged in the order the plan reaches them, and the first one reached barely pays anything.
Does it matter which card I pay off first on a two-year plan?
It is worth $633.46 at the same $916 a month, and two months of time: snowball lands in twenty-four months and avalanche in twenty-two. Snowball clears Card D in month 4, Card C in month 9, Card B in month 15 and Card A in month 24; avalanche clears Card A in month 11, Card B in month 17, Card C in month 21 and Card D in month 22.
What if I only pay the minimums on $15,000?
The $400 in minimums clears the balance in 81 months — nearly seven years — and costs $11,271.94 in interest, a total bill of $26,271.94. The twenty-four-month plan is charged $3,477.64, a saving of $7,794.30. The plan also finishes 3.375 times faster: 24 months against 81. Month 1 of the minimums is charged the same $265.83 the plan is, but only $134.17 of that $400 reaches principal, against $650.17 of the plan's first payment. Avalanche on the minimums takes the same 81 months and costs $11,243.13 — just $28.81 less.
How long does it take to pay off $15,000 in 2 years?
Two years, by definition — but only if you send $916 a month, which is 2.290 times the $400 in minimums. The deadline is exact: $916 lands the payoff in twenty-four months and $915 adds a twenty-fifth and takes the interest to $3,484.06. Avalanche's own deadline sits lower, at $858, and $857 pushes it to twenty-five months. The minimums alone take 81 months on the same portfolio and cost $11,271.94 in interest.
What is the blended interest rate on this portfolio?
21.267% a year, weighted by balance: $6,000 at 24%, $4,000 at 21%, $3,000 at 19% and $2,000 at 17% work out to $3,190.00 of annual interest on $15,000. One twelfth of that is 1.77222%, which is $265.83 on the opening balance — $120.00 on Card A, $70.00 on Card B, $47.50 on Card C and $28.33 on Card D. By month 24, under the plan, the monthly interest is down to $12.93 — 20.56 times less than month 1.
What happens in the last month of the plan?
Month 24 is the only payment that is not a round step. The plan's twenty-three full payments are $916, $846, $766 and $666, and the last one is $659.64, because the balance runs out partway through the month — Card A's $150 minimum would have taken the payment to $666, and $6.36 of that is never needed. Of that final $659.64, $646.71 reaches principal and $12.93 is interest, which is 1.96% of the payment against 29.02% in month 1.