Last updated July 18, 2026
Snowball versus avalanche, side by side
| Avalanche | Snowball | |
|---|---|---|
| Order balances by | Highest APR first | Smallest balance first |
| Minimizes total interest | Yes | No |
| First win arrives | Slower, if the highest-rate card is also large | Fast, often within a month or two |
| Best suited for | People motivated by the math | People motivated by visible progress |
Avalanche is mathematically optimal every time: paying the highest-rate balance first always costs less in total interest than any other order. Snowball trades some of that savings for a psychological head start, an early payoff that keeps the plan alive. Neither is wrong; the wrong choice is the one you abandon in month four.
The month-by-month mechanics
This calculator doesn't use one closed-form equation; it steps through the balance a month at a time, the way a statement actually works. On an $8,000 balance at 19.9 percent APR with a $250 payment, the monthly rate is 0.199 divided by 12, about 0.016583. Month one's interest is 8,000 times 0.016583, near $133; the $250 payment covers that and puts about $117 toward principal, leaving roughly $7,883 owed. Next month, interest is charged on the smaller balance, so a bit more of the same payment reaches principal. Repeat until zero. At $250 a month, this particular balance clears in about 43 months with roughly $2,700 in total interest.
What an extra payment buys you
| Monthly payment | Months to payoff | Total interest |
|---|---|---|
| $250 | 43 | $2,700 |
| $300 | 33 | $1,980 |
| $400 | 23 | $1,290 |
Every extra dollar goes straight to principal, which shrinks the balance that all future interest gets charged against. That's why a bigger payment pays off twice over: the debt clears faster, and it costs less to clear.
Applying either strategy across multiple balances
If you're carrying more than one balance, run each one through this calculator separately in the order your chosen strategy dictates, avalanche by rate or snowball by size, then roll the freed-up payment from a cleared balance into the next one on the list. The Consumer Financial Protection Bureau's general guidance is to pay more than the minimum whenever the budget allows, regardless of which ordering strategy you pick.
Sources: CFPB on minimum payments, CFPB on paying down debt.
Related calculators
- Personal Loan Calculator, for consolidating into a fixed installment loan
- Compound Interest Calculator, the same math working in your favor instead