You can find strong opinions everywhere about avalanche versus snowball. We took a different approach. We built a calculation engine, ran 127 test scenarios, and looked at what the numbers actually show across 10 realistic debt situations.
The three methods in plain English
Avalanche means you pay the minimum on every account and put any extra money toward the debt with the highest interest rate first.
Snowball uses the same minimum payments, but sends extra money to the smallest balance first, regardless of rate.
Minimum-only means you never add extra. You just pay what each lender requires, and as debts disappear, that freed-up money gets split proportionally across what's left.
Scenario 1: One high-rate card and one low-rate card
Imagine Card A with a $5,000 balance at 24% APR and a $150 minimum, plus Card B with $8,000 at 6% APR and a $200 minimum. You can afford an extra $300 per month on top of minimums.
| Strategy | Months to debt-free | Total interest |
|---|---|---|
| Avalanche | 30 | $2,180 |
| Snowball | 32 | $2,470 |
| Minimum-only | 91 | $5,840 |
Avalanche wins here by $290 in interest. Snowball takes two extra months because it happens to pay off Card A first anyway (it's the smaller balance and the higher rate, so both methods agree). The real gap shows up when you compare either strategy to minimum-only, which costs nearly three times as much interest.
Scenario 2: Several small debts and one large low-rate loan
This one looks like many households: four credit cards between $500 and $2,000 each, with rates from 16% to 22%, plus a mortgage-style loan of $40,000 at 5% with a $400 minimum. Extra payment available: $400 per month.
| Strategy | Months to debt-free | Total interest |
|---|---|---|
| Avalanche | 96 | $9,400 |
| Snowball | 102 | $9,860 |
| Minimum-only | 168 | $18,200 |
Avalanche finishes six months sooner and saves $460 in interest. Snowball has a different advantage: your first three debts are gone by months 4, 9, and 15. Three clear wins in the first 15 months. For some people, that momentum is worth the extra $460.
Scenario 7: When the minimum doesn't cover the interest
This is the scary one. A Synchrony or Lowe's card at $4,200 and 32% APR with an $80 minimum, plus two other cards totaling $6,000 at 18%. You can add $200 per month beyond minimums.
On the Lowe's card alone, monthly interest runs about $112 against an $80 minimum. In minimum-only mode, the balance grows forever.
| Strategy | Months to debt-free | Total interest |
|---|---|---|
| Avalanche | 41 | $3,800 |
| Snowball | 44 | $4,150 |
| Minimum-only | never (cap reached) | n/a |
If any card charges more interest per month than your minimum payment covers, minimum-only cannot work. You need a strategy that deliberately attacks that account. Avalanche gets there in 41 months; snowball takes 44.
What we saw across all 127 test scenarios
Avalanche always wins on total interest. That's built into how the math works.
The average margin over snowball is about 2% to 4% of total interest. Real money, but usually not life-changing.
Snowball's first payoff win typically arrives 30% to 60% sooner than avalanche's when debt sizes are mixed. That timing difference is the whole psychological case for snowball.
In roughly 15% of scenarios, minimum-only actually beat snowball on interest. That sounds backwards, but proportional redistribution sometimes sends more money toward high-rate debts than snowball's smallest-first targeting. Surprising, but we verified it.
Which strategy fits you?
Choose avalanche if you stay motivated by the numbers and can wait for your first debt to disappear. It especially shines when your highest-rate debts are also your largest balances, which is the most common situation.
Choose snowball if you need an early win to keep going. It works well when high-rate debts are small (you'd knock them out quickly either way), or when you've quit debt plans before because progress felt too slow.
Avoid minimum-only if any debt has a minimum payment below its monthly interest charge. The math literally cannot reach zero that way.
Run the numbers on your own debts
Try the WIMM debt reducer demo at app.wimm.money/demo?mode=debt. You will land on the Debt tab with sample balances and rates pre-loaded; the calculator runs all three strategies side by side. There is also a What-If slider for extra monthly payment. Every scenario in this article takes seconds to reproduce.
The full calculation engine lives at /features/debt-reducer.
Try WIMM today
The demo loads with realistic data and no signup. See what this article describes in action.