Debt Avalanche vs. Debt Snowball: We Ran the Numbers on Both
Same $14,000 of debt, same $750 monthly budget: the avalanche saves $422 in interest, the snowball closes two accounts sooner. Here is the month-by-month arithmetic behind both, including what minimum-only payments really cost.
The two best-known debt payoff plans differ in exactly one sentence. Both say: pay the minimum on everything, then throw every spare dollar at one debt. The avalanche aims that dollar at the highest interest rate first. The snowball aims it at the smallest balance first, on the theory that closing an account early keeps you in the game.
Most of the advice about which is better is opinion. This article runs both plans on the same fixed scenario instead, so you can see what each one actually costs and when each one actually ends.
The scenario
Three debts, a $750 total monthly debt budget. The minimums are defined the way card agreements usually define them: the greater of a fixed floor ($35) or a percentage of the current balance — 2.5% on the credit card, 3% on the store card. The personal loan has a fixed $185 payment. No new borrowing during the payoff, and the rates below are held constant.
| Account | Balance | APR | Starting minimum |
|---|---|---|---|
| Store card B | $2,400 | 28.99% | $72.00 |
| Credit card A | $6,000 | 24.99% | $150.00 |
| Personal loan C | $5,600 | 11.49% | $185.00 |
Minimums add up to $407, so every month there is $343 of extra money. The only decision in the whole plan is where that $343 goes.
The results at $750 a month
| Method | Order | Debt-free | Total interest |
|---|---|---|---|
| Avalanche | B, A, C | 23 months | $2,637 |
| Snowball | B, C, A | 23 months | $3,059 |
Both plans land on the same finish line — just under two years — but the avalanche gets there for $422 less. That gap is the entire price of the snowball's motivational structure in this scenario. It is not trivial, and it is not catastrophic; it is about one extra month of the budget.
The per-account timeline is where the two plans feel different from the inside:
| Account | Closed by avalanche | Closed by snowball |
|---|---|---|
| Store card B | Month 7 | Month 7 |
| Credit card A | Month 19 | Month 23 |
| Personal loan C | Month 23 | Month 15 |
By month 15 the snowball runner has closed two of three accounts; the avalanche runner has closed one. If you are the kind of person who needs visible progress to keep paying, that early momentum has real value — just be honest that it is purchased at $422 here. Notice also that both plans happened to start with the same account: the smallest balance was also the highest rate. When that is true in your own debts, the debate is moot for the first stretch anyway.
Tighten the budget and the story holds
Rerun the same debts on a $620 monthly budget and the ranking does not change: both plans finish in 29 months, the avalanche costs $3,499 in interest and the snowball $3,914 — a $415 premium. The method ranking is stable; what actually moves the outcome is the size of the extra payment.
The real villain: minimum-only payments
For scale, run the two cards in the table with no extra money at all — minimum payments only, recalculated each month as the balance falls. That schedule takes 396 months — 33 years — and about $27,800 in interest to retire $8,400 of debt. (Assumes the greater of $35 or the balance percentage, as above.)
This is why the avalanche-versus-snowball argument is a second-order question. Either structured plan turns 33 years into roughly two. The order you pick moves the interest bill by hundreds of dollars; the extra payment moves it by tens of thousands.
A decision rule that costs nothing. Sort your debts by rate. If the highest and lowest APRs are within a couple of percentage points, pick snowball — the interest difference will be small and the motivation is free. If there is a wide gap, like the 17.5 points between the store card and the loan here, lean avalanche and find your motivation in the shrinking interest line instead.
Where these numbers come from, and where they can drift
The simulation behind the tables is a month-by-month amortization: interest accrues monthly at one-twelfth of the APR on the running balance, payments land on the same day each month, minimums are always funded first, and the extra payment goes to the current target. Three simplifications are worth knowing so you can judge how far real life could deviate.
First, real cards accrue interest on average daily balances. On balances this size, the monthly approximation differs from the daily method by single-digit dollars over the full payoff — not enough to change any conclusion. Second, rates are held constant, and real rates can move. If a card's APR rises mid-payoff, both totals grow, but the plan that had already retired that card is hurt less — one more quiet argument for front-loading the expensive debt rather than the small one. Third, the model ignores late fees, new borrowing, and credit-score effects entirely. Fees and new borrowing are the two things that break payoff plans in practice, which is why the automation in the next section matters more than the ordering debate.
One real-world effect works in your favor: as balances fall, utilization falls with them, and credit scores generally rise during a structured payoff — which is roughly when you want to be refinancing whatever is left. Closing accounts shortens your average account age slightly, which costs a few points temporarily; that is a 2027 problem for the 2026 version of you who is debt-free.
One lever most plans forget: the balance transfer
Moving the $6,000 card to an 18-month 0% balance transfer offer with a 3% fee changes the arithmetic sharply. The fee is $180, one-time. The interest being avoided on card A runs about $125 a month at 24.99%, so the transfer pays for itself in about six weeks — if the balance is actually cleared inside the promotional window and nothing new goes on the emptied card. If the promo expires with half the balance still sitting there, the remaining debt reverts to the full APR and the advantage evaporates. The offer is a tool for people whose payoff plan already works.
How to run either plan without spreadsheet fatigue
Automate the minimums on everything on payday, then send one extra payment a month to your chosen target — the day after payday, so the money never sits where it can be spent. When a debt dies, redirect its entire minimum plus the extra to the next one; that rolling payment is what makes later debts collapse quickly. Recompute your finish date once a month, not daily. The number moving slowly is normal; the number moving is the point.
Whichever order you pick, the honest summary of the simulation is this: the method you choose changes the cost by a few hundred dollars. The budget you choose changes it by a few decades.
