Debt Payoff Calculator
Compare the snowball and avalanche methods to see how fast you can clear your debts, and what the difference in total interest actually amounts to.
Avalanche always wins — by an amount that peaks in the middle
Avalanche pays the highest interest rate first; snowball pays the smallest balance first. Both differ only in where the extra money goes — so if there is no extra money, there is nothing to differ about. Running the same four debts at several extra payments:
| Extra per month | Avalanche | Snowball | Avalanche saves |
|---|---|---|---|
| $0 | 98 mo, $7352 | 98 mo, $7352 | nothing |
| $50 | 57 mo, $4302 | 69 mo, $5271 | $969 (18%) |
| $100 | 40 mo, $3113 | 55 mo, $4337 | $1224 (28%) |
| $200 | 32 mo, $2077 | 33 mo, $2254 | $178 (8%) |
| $400 | 22 mo, $1302 | 23 mo, $1399 | $97 (7%) |
The gap is not monotonic, which is the part that gets left out of the usual argument. It is exactly zero when you are paying only the minimums — both take 98 months and cost $7352, identically. It peaks around $100 extra, worth $1224. And it shrinks again to $97 at $400, because by then everything clears quickly whichever order you pick.
So the choice matters most to someone paying a moderate amount above the minimums, and barely at all to someone paying either nothing extra or a great deal. At $200 extra the whole difference is $178 on $13,600 borrowed — about 1.3% of the principal.
And snowball buys an earlier first win
The trade is real rather than rhetorical. On the same debts at $200 extra, here is the order things actually get cleared:
| Strategy | Order cleared |
|---|---|
| Avalanche | Store card (month 6) → Phone plan (month 21) → Credit card (month 25) → Car loan (month 32) |
| Snowball | Phone plan (month 2) → Store card (month 8) → Credit card (month 26) → Car loan (month 33) |
Snowball closes an account in month 2 instead of month 6 — a 4-month head start on having one fewer thing to think about. If crossing something off the list is what keeps you paying, that is worth something real, and here it costs $178.
The honest version: avalanche is arithmetically better and never loses, but the margin is often smaller than the argument about it. Both beat paying only the minimums by an enormous distance — 98 months down to 32 at $200 extra — and that gap dwarfs the difference between the two strategies. Work out the number for your own debts before deciding which side to be on.
How to use
- List each debt with its balance, rate and minimum payment.
- Enter what you can pay in total each month.
- Compare the two strategies side by side.
- Pick the one you will actually stick to.
Frequently asked questions
What is the difference between snowball and avalanche?
Which debt gets the extra money. Avalanche targets the highest interest rate first, which is mathematically optimal and costs the least in total. Snowball targets the smallest balance first, which clears individual debts sooner and gives visible early progress.
Which one should I choose?
Avalanche saves more money; snowball keeps more people going. Research on real behaviour has repeatedly found that the motivational effect of clearing a debt entirely is worth something real, and a plan followed to completion beats an optimal plan abandoned in month four. The gap in total interest is often smaller than people assume — worth checking for your own numbers before deciding.
Why do minimum payments take so long?
Because a minimum is typically calculated as a small percentage of the balance, so it falls as the balance falls, stretching the term enormously. On a credit card, paying only the minimum can take decades and cost more in interest than the original debt. Paying any fixed amount above the minimum shortens it dramatically.
Does the order matter if all my rates are similar?
Barely. When rates are close, the two strategies produce nearly identical results, so choose on whichever basis motivates you. The order matters most when one debt carries a much higher rate than the rest.
Should I consolidate instead?
It depends entirely on the rate and the fees, and it carries a real risk: consolidating without changing the spending that created the debt frequently ends with the consolidated loan plus fresh balances on the cleared cards. Consolidation restructures a debt; it does not reduce it.
Does this account for new spending?
No — it assumes the balances only go down. Any new borrowing during the payoff period extends it, often by more than expected. This is a planning tool rather than financial advice, and a real plan needs to account for what happens if the spending continues.
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