Minimum payments come out of this first. Whatever is left goes to the debt at the top of your payoff order.
Each debt also has its own advanced fields: type, annual fee, ongoing new monthly charges, and an exclude switch. Open a row with the ⋯ button.
Snowball vs avalanche, same numbers
| Method | Debt-free in | Months | Total interest | Total paid |
|---|
Payoff order
| # | Debt | Type | Starting balance | APR | Payoff month |
|---|
Month-by-month schedule
| Month | Payment | Interest | Principal | Remaining |
|---|
The four rows above are an example, not your debts — overwrite them. Prefer a file you can edit?
What the twelve runs say, in four numbers
3 of 12 portfolios clear in exactly the same month under both orders — the order moved the interest, not the calendar. The middle gap is $1,342.41, well under the $2,506.24 average, because two large portfolios ($50,000 and $60,000) carry $16,013.83 of the $30,074.90 total. And the lever nobody argues about — an extra $100 a month — is worth $1,559.67 on average, 62% of the entire method gap, without changing the order at all. Which means: for most balances, the order is worth a few hundred dollars and the extra payment is worth the calendar.
Every money figure on this page is computed by this site's public payoff engine from the inputs printed below. The portfolios are constructed, not submitted by users. Which inputs are printed figures and which are my own assumptions is listed line by line in the inputs section; read that before you re-run anything.
The short answer, before the table
"Does it work" is two questions wearing one coat. First: does clearing the smallest balance first get you out of debt? Yes, every time — all twelve portfolios reach zero under both orders. Second: is the snowball the cheapest of the two orders? No, not here. The avalanche — highest rate first — paid less interest in 11 of the 12, and the same months or fewer in all twelve.
What the numbers do not support is the sentence people usually add: "so the snowball is a bad idea." On a third of these portfolios the two orders finished in the same month, and the money difference on those three was $81.18, $123.69 and $0.00. The snowball costs real money on long plans with wide rate spreads, and it costs almost nothing on short plans with narrow ones. The twelve runs below show where the line sits.
Where every number on this page comes from
This is the part most comparison pages skip, and it is the part that lets you check me. Six inputs sit behind every row in the table, and they do not carry the same authority. The ledger below says, for each one, what it is, where it came from, and whether it is a figure printed on this page or my own assumption.
| Input | Where it comes from | Kind |
|---|---|---|
| Each card's balance, APR and minimum payment | Printed card by card in the inputs table below | printed here, my construction |
| The minimum payments themselves | Printed card by card in the inputs table below, not derived from a formula | printed here, my construction |
| $300 a month of extra payment, identical in all twelve | Stated in the subhead, the caption and the reproduce section | my assumption |
| Minimums held at their opening dollar amount for the whole run | Stated in the reproduce section | my assumption |
| Interest = balance × APR ÷ 12, charged monthly before payment; no fees, no new charges | Stated in the reproduce section; it is the engine's rule | engine convention |
| Payoff order: snowball smallest balance first, tie to the higher rate; avalanche highest rate first, tie to the smaller balance | Stated in the reproduce section; the tie rule is what this site's calculator does | engine convention |
Two flags, because this is where a page like this usually cheats. First, the minimum payments are not quoted from any card issuer and are not the output of a formula. There is no single published rule for card minimums, so each minimum here is a figure I wrote down myself, card by card: roughly 2.5% of the opening balance with a $25 floor, close to that rule but not equal to it on every card, because I kept round numbers instead of deriving them. Do not read any row in the inputs table as "what an issuer would charge" — read it as "the number this run used". Second, the minimums are held fixed at their opening amount for the whole run, which is my choice made so both orders face an identical budget. Real issuers step the minimum down as the balance falls, and if yours does, your months will run longer than these. The direction of the gap stays the same; the size does not.
That is the honest limit of a constructed portfolio, and it is why every row prints its inputs: you can change the rule and re-run it yourself. Nothing on this page is a real borrower's statement, and nothing on this page claims to be one.
The inputs, card by card
Twelve portfolios, 2 to 6 cards each, $5,000 to $60,000 in total. Every card's balance, rate and minimum is here so the whole page can be rebuilt from scratch without trusting a single number I typed into a sentence.
| Portfolio | Card | Balance | APR | Minimum |
|---|---|---|---|---|
| Two cards, $5k | A | $3,000 | 24% | $75 |
| B | $2,000 | 19% | $50 | |
| Three cards, $11k | A | $5,000 | 26% | $125 |
| B | $3,500 | 22% | $88 | |
| C | $2,500 | 17% | $63 | |
| Four cards, $20k | A | $8,000 | 27% | $200 |
| B | $6,000 | 23% | $150 | |
| C | $4,000 | 19% | $100 | |
| D | $2,000 | 15% | $50 | |
| Five cards, $50k | A | $15,000 | 25% | $375 |
| B | $11,000 | 22% | $275 | |
| C | $10,000 | 20% | $250 | |
| D | $8,500 | 17% | $213 | |
| E | $5,500 | 15% | $137 | |
| Five cards, $60k | A | $18,000 | 25% | $450 |
| B | $13,200 | 22% | $330 | |
| C | $12,000 | 20% | $300 | |
| D | $10,200 | 17% | $255 | |
| E | $6,600 | 15% | $165 | |
| Six store cards, $7.4k | A | $1,200 | 29% | $36 |
| B | $900 | 26% | $27 | |
| C | $1,500 | 24% | $45 | |
| D | $700 | 22% | $25 | |
| E | $2,000 | 20% | $50 | |
| F | $1,100 | 18% | $33 | |
| Two cards, both near 30% | A | $9,000 | 29.99% | $270 |
| B | $4,000 | 27.99% | $120 | |
| Five cards, $36k | A | $12,000 | 21% | $300 |
| B | $9,000 | 18% | $225 | |
| C | $7,000 | 16% | $175 | |
| D | $5,000 | 14% | $125 | |
| E | $3,000 | 12% | $75 | |
| Three cards, wide spread | A | $15,000 | 28% | $375 |
| B | $2,000 | 12% | $50 | |
| C | $8,000 | 20% | $200 | |
| Four equal balances, $24k | A | $6,000 | 24% | $150 |
| B | $6,000 | 22% | $150 | |
| C | $6,000 | 18% | $150 | |
| D | $6,000 | 15% | $150 | |
| One big + three small | A | $30,000 | 23% | $750 |
| B | $1,500 | 26% | $45 | |
| C | $1,200 | 21% | $36 | |
| D | $800 | 19% | $25 | |
| Six cards, $17.3k | A | $4,500 | 25% | $113 |
| B | $3,800 | 23% | $95 | |
| C | $3,100 | 21% | $78 | |
| D | $2,600 | 19% | $65 | |
| E | $1,900 | 17% | $48 | |
| F | $1,400 | 15% | $35 |
The twelve portfolios, one at a time
Each portfolio is run twice with identical inputs: same balances, same rates, same minimums, same $300, same order of operations. The only thing that changes is which card the extra $300 attacks each month. "Gap" is snowball interest minus avalanche interest, so a positive gap is money the snowball order paid for the privilege of clearing small balances first.
| Portfolio | Cards | Balance | Spread | Snowball | Avalanche | Gap |
|---|---|---|---|---|---|---|
| Two cards, $5k | 2 | $5,000 | 5% | 15 mo / $745.84 | 15 mo / $664.66 | $81.18 |
| Three cards, $11k | 3 | $11,000 | 9% | 30 mo / $3,372.97 | 28 mo / $2,722.57 | $650.40 |
| Four cards, $20k | 4 | $20,000 | 12% | 47 mo / $9,990.95 | 42 mo / $7,431.46 | $2,559.49 |
| Five cards, $50k | 5 | $50,000 | 10% | 70 mo / $31,572.74 | 56 mo / $24,381.58 | $7,191.16 |
| Five cards, $60k | 5 | $60,000 | 10% | 74 mo / $39,765.88 | 58 mo / $30,943.21 | $8,822.67 |
| Six store cards, $7.4k | 6 | $7,400 | 11% | 21 mo / $1,465.55 | 21 mo / $1,341.86 | $123.69 |
| Two cards, both near 30% | 2 | $13,000 | 2% | 30 mo / $5,188.49 | 29 mo / $4,699.05 | $489.44 |
| Five cards, $36k | 5 | $36,000 | 9% | 54 mo / $14,754.99 | 48 mo / $11,839.48 | $2,915.51 |
| Three cards, wide spread | 3 | $25,000 | 16% | 53 mo / $15,626.75 | 44 mo / $11,070.21 | $4,556.54 |
| Four equal balances, $24k | 4 | $24,000 | 9% | 44 mo / $8,036.56 | 44 mo / $8,036.56 | $0.00 |
| One big + three small | 4 | $33,500 | 7% | 49 mo / $17,739.91 | 45 mo / $16,502.78 | $1,237.13 |
| Six cards, $17.3k | 6 | $17,300 | 10% | 43 mo / $6,918.11 | 39 mo / $5,470.42 | $1,447.69 |
Add the gap column up and you get $30,074.90. That is a real total and a bad headline, because two rows carry more than half of it: the $50,000 portfolio at $7,191.16 and the $60,000 at $8,822.67, together $16,013.83. Sort the twelve by gap and the middle one is $1,342.41, and five sit under $700 ($0.00, $81.18, $123.69, $489.44, $650.40). A reader who takes the average as "what the snowball costs" is reading two large portfolios stretched across twelve rows.
Spread times time, not the size of the debt
The gap is not a function of how much you owe. Sort the same twelve by rate spread and the pattern shows in one screen: portfolios with the same spread land anywhere from $0.00 to $8,822.67, and what separates them is how many months the balance sits on the expensive card.
| Spread | Portfolio | Balance | Snowball months | Gap |
|---|---|---|---|---|
| 2% | Two cards, both near 30% | $13,000 | 30 | $489.44 |
| 5% | Two cards, $5k | $5,000 | 15 | $81.18 |
| 7% | One big + three small | $33,500 | 49 | $1,237.13 |
| 9% | Three cards, $11k | $11,000 | 30 | $650.40 |
| 9% | Four equal balances, $24k | $24,000 | 44 | $0.00 |
| 9% | Five cards, $36k | $36,000 | 54 | $2,915.51 |
| 10% | Six cards, $17.3k | $17,300 | 43 | $1,447.69 |
| 10% | Five cards, $50k | $50,000 | 70 | $7,191.16 |
| 10% | Five cards, $60k | $60,000 | 74 | $8,822.67 |
| 11% | Six store cards, $7.4k | $7,400 | 21 | $123.69 |
| 12% | Four cards, $20k | $20,000 | 47 | $2,559.49 |
| 16% | Three cards, wide spread | $25,000 | 53 | $4,556.54 |
Three portfolios share a ten-point spread and their gaps run $1,447.69, $7,191.16 and $8,822.67, a sixfold difference from payoff length alone. Two portfolios sit within two points of each other on spread and their gaps are $123.69 and $8,822.67. The sentence people repeat, "the snowball hurts more on bigger debts", survives only if "bigger" quietly means "slower", which is a different word.
The one case that ties to the cent
The $24,000 portfolio is four $6,000 balances at 24%, 22%, 18% and 15%, four $150 minimums, $300 extra. Both orders finish at month 44 for $8,036.56, with the same interest on each card: $1,049.04 on the 24% card, $2,337.29, $2,480.12 and $2,170.12. Run the snowball loop by hand and it sorts by smallest balance, finds all four equal, and breaks the tie by the higher rate: 24%, 22%, 18%, 15%. Run the avalanche loop and it sorts by the highest rate and gets the same list. Same order, same arithmetic, same answer, and the $0.00 in the gap column is the arithmetic agreeing with itself rather than a rounding artefact.
Raise the extra to $400 on that same portfolio and it drops from 44 months to 38 and from $8,036.56 to $6,867.91: $1,168.65 saved by the payment, in a portfolio where the order was worth exactly nothing.
Where the snowball costs money but not time
Three portfolios finish in the same month under both orders: the $5,000 pair (15 months, $745.84 against $664.66), the six store cards (21 months, $1,465.55 against $1,341.86) and the four equal balances ($8,036.56 both ways). On those the gap column reads $81.18, $123.69 and $0.00. The order moved the interest and did not move the calendar by a single month.
If your horizon is measured in months rather than in dollars, that third of the sample is the relevant fact. You are not choosing between finishing early and finishing cheap; you are choosing between finishing the same month with slightly less interest and finishing the same month with slightly more. Nobody quits a plan over $81.18, and nobody should feel clever about avoiding it either.
What the numbers say, and what they do not
What they say: clearing the smallest balance first is a real method with a real price; the price is bounded by the rate spread multiplied by how long the balance stays on the expensive card; and on short plans the price is close to zero. What they do not say: that the snowball is motivational, that people stick to it, that the visible early win changes behaviour. None of that is in this arithmetic. A payoff loop has no behaviour term, and this page does not import one. The behavioural case for the snowball may well be true; it is not measured here, and a page that calculates interest has no standing to claim it.
The one number that does speak to the decision is the extra payment. Going from $300 to $400 a month on these same twelve saved $1,559.67 of interest on average, 62% of the $2,506.24 average method gap, leaving the order untouched. On the equal-balance portfolio it was $1,168.65 against a method gap of $0.00. The order is free to change and worth having on long, wide-spread plans. The extra payment is worth having on all twelve.
One more thing the table cannot show, and that this page will not pretend to: the cut at twelve portfolios is mine. Twelve is enough to see that spread and time drive the gap, and not enough to say "the snowball costs 19.4%" as though that were a property of the method. It is the property of these twelve. If your spread is 2 points and your payoff is under two years, the row that matters is the $13,000 pair at $489.44, not the $60,000 one.
Reproduce these numbers
Every figure here comes from /api/payoff. Post a portfolio, an extra amount and a method, and you get months, total interest and per-card interest back. The wide-spread portfolio, shown in full:
{"debts": [{"name": "A", "balance": 15000, "apr": 28, "minPayment": 375}, {"name": "B", "balance": 2000, "apr": 12, "minPayment": 50}, {"name": "C", "balance": 8000, "apr": 20, "minPayment": 200}], "extra": 300, "method": "snowball"}
That returns 53 months and $15,626.75. Switch method to avalanche and it returns 44 months and $11,070.21, the $4,556.54 gap in the table.
The loop behind it, in full, so it can be re-implemented without me. Each month: add balance × APR ÷ 1200 to every open card and to the running interest total; pay each open card the smaller of its minimum and its balance; then send the leftover budget ($300 + the minimums of the cards still open) down the fixed order, card by card, never past the card's own balance; stop when every balance is at or below one cent. APR goes in as a percentage, not a decimal.
The order is fixed once, at the start, from the opening balances: smallest first for the snowball with ties going to the higher rate, highest rate first for the avalanche with ties going to the smaller balance. Re-sorting every month on the current balance changes the tie cases and reports different months, which is why it is done once.
Two conventions to carry over: minimums stay at their printed dollar amount for the whole run instead of stepping down with the balance, and nothing is added to any card after month one. Change either and you are running a different comparison: a legitimate one, just not this one.
Frequently asked
Does the debt snowball actually work?
It clears the debt, and in 3 of these 12 portfolios it clears it in the same month as the avalanche. What it does not do is save the most interest: the avalanche was cheaper in 11 of 12, by $2,506.24 on average and $1,342.41 at the median. So the order works, the size of its win depends on your rate spread and payoff length, and on a short plan with a narrow spread the two orders are worth the same dollars.
How much extra interest does the snowball cost on these twelve?
$30,074.90 across the twelve, against $155,178.74 paid under the snowball order: 19.4%. That total is not the number to plan with. The $50,000 and $60,000 portfolios carry $16,013.83 of it, the middle portfolio is $1,342.41, and five sit under $700.
Is an extra $100 a month worth more than picking the better order?
On these twelve, yes. Going from $300 to $400 saved $1,559.67 of interest on average, 62% of the $2,506.24 average method gap, and it changed no orders at all. The order is free to switch; the extra payment is what moves the calendar.
When do the two orders finish in the same month?
In 3 of the 12: the $5,000 two-card portfolio, the six store cards at $7,400, and the four equal balances at $24,000. In those the snowball costs $81.18, $123.69 and $0.00: dollars, no days. The other nine finish 1 to 16 months sooner under the avalanche.
Are these real people's debts?
No. They are twelve portfolios assembled for this page from common card counts, balances and rate spreads, and every card's balance, rate and minimum is printed above so you can re-run any of them. The minimum-payment rule is my stated assumption, not a quoted issuer formula.
Does the snowball work better because of motivation?
That claim is not measured here. A payoff loop has no behaviour term, so it cannot tell you whether clearing a small balance in month 9 keeps someone on the plan in month 20. It may well be true; this page calculates interest and does not put a number on something it cannot compute.