Debt Snowball vs. Avalanche: Which Pays Off Debt Faster?
Both methods start identically: pay the minimum on every debt, then send every spare dollar at exactly one target until it’s gone, then move to the next. They disagree only on which debt is the target — and that one difference is enough to change your payoff date, your total interest, and which account disappears first.
The two strategies, one paragraph each
Avalanche always targets whichever debt currently has the highest interest rate. Mathematically, this is the fastest way to minimize total interest, because every extra dollar is always fighting the most expensive balance you have. Snowball always targets whichever debt currently has the smallest balance, and sticks with that choice until it’s paid off, even if another balance drops lower in the meantime. The appeal isn’t the math — it’s that an entire account, and the minimum payment and paperwork that came with it, disappears as fast as possible. Both rules only govern where your extra dollars go; minimum payments still go out to every debt every month either way. See the full methodology for exactly how targets, ties, and rollovers are computed.
A walkthrough with two real debts
Take a $500 store card at 12% APR with a $25 minimum, and a $1,000 credit card at 24% APR with a $20 minimum, plus $50/month extra to put toward either one — $95/month total. Month 1 is identical no matter which strategy you pick, because nothing has diverged yet: $25.00 interest, $70.00 of principal, $1,430.00 remaining across both debts combined. From month 2 the strategies disagree on where the $50 extra goes — avalanche sends it to the 24% card, snowball sends it to the smaller $500 balance — and the two schedules drift apart by small amounts every month after that.
Run the whole thing to zero and the difference is real but modest: both strategies clear both debts in exactly 19 months, but avalanche pays $247.50 in total interest against snowball’s $292.80 — a $45.30 saving for changing nothing but the target order. Snowball’s payoff isn’t all downside, though: its target, the $500 card, is gone by month 7, ten months before avalanche clears its first debt at month 17. If what keeps you paying is watching an account hit zero, snowball delivers that feeling ten months sooner, for $45.30. Load this exact scenario in the calculator → and watch both schedules side by side.
Why avalanche usually wins on total interest
This isn’t a coincidence of the numbers above — it follows from a simple argument: every dollar of extra payment earns a guaranteed “return” equal to whatever rate it’s currently deployed against, and avalanche always deploys the next dollar at the single highest rate available. For any set of debts whose rates stay fixed for the life of the loan, that greedy choice is optimal — no other targeting order can produce less total interest. Our engine’s randomized test suite backs this up empirically too: across 150 randomly generated multi-debt scenarios with fixed rates, avalanche’s total interest was never higher than snowball’s, not once.
The 0% promo wrinkle: when snowball actually wins
That guarantee has exactly one hole: rates that don’t stay fixed. Avalanche decides where to send money based on each debt’s current rate, so a 0% introductory promo looks, correctly, like free money right now — and avalanche starves that balance of extra payments for as long as the promo lasts. The problem is what happens after. Take an $800 store card at 29% APR with a 6-month 0% intro and a $20 minimum, alongside a $1,500 card at a flat 16% APR and a $30 minimum, with $80/month extra. For six months, avalanche is “correct” and pours every spare dollar into the 16% card, leaving the store card sitting at 0% untouched beyond its minimum. But when the promo lapses to 29% in month 7, that store card still has roughly $680 left on it — and it’s now the single most expensive balance either debt will carry for the rest of the schedule.
Snowball, meanwhile, never looked at rates at all — it targeted the $800 store card from day one purely because it was the smaller balance, and had already paid it down to about $200 by the time the promo would have expired. Run both to completion: snowball finishes in 20 months for $289.22 in total interest; avalanche takes 21 months for $302.96. Snowball wins on both counts here — not because it’s smarter about rates, but because its balance-based rule happened to prioritize the one debt with a cliff coming. See the methodology for exactly how promo periods are modeled and why avalanche can’t see this coming.
The honest psychology case for snowball
The case for snowball isn’t just folk wisdom. Gal and McShane’s 2012 study in the Journal of Marketing Research, analyzing real accounts from a debt-settlement firm, found that closing out individual debt accounts — regardless of their dollar balance — predicted whether someone eliminated all their debt far better than the interest-rate math did. That’s the actual argument behind Dave Ramsey’s two-decade popularization of the “debt snowball” name: momentum from closing accounts is a measured behavioral effect, not just a nice story. What neither that study nor the numbers above can tell you is which effect is bigger for you specifically — the guaranteed interest savings, or the motivation of an earlier first win.
So which should you actually choose?
If the interest gap between the two on your real numbers is small — as it often is — pick whichever keeps you coming back every month, because a plan you abandon in month four beats neither. If the gap is large, or you’re carrying a 0% promo that’s about to expire, run your actual numbers before assuming avalanche wins by default. That’s what the calculator is for: enter your real balances, rates, and minimums, and it runs both schedules side by side so you’re deciding from your own numbers, not a rule of thumb. For how much of that decision really comes down to your extra payment amount rather than the strategy itself, see How Much Extra Should You Pay?
Limitations
Both schedules assume your APRs, minimums, and extra payment stay exactly as entered for the life of the plan, compound monthly rather than daily, and ignore fees, credit-limit changes, and any impact on your credit score from closing an account early. This page, and the calculator behind it, is an educational comparison of two well-documented strategies — not financial advice for your specific situation.