Debt Payoff Calculator (Snowball vs. Avalanche)
Enter each debt's balance, interest rate, and minimum payment, plus how much extra you can put toward debt each month. Compares the snowball method (smallest balance first) against the avalanche method (highest interest rate first) side by side — total interest, payoff date, and how much one strategy saves over the other.
Smallest balance first
Highest interest rate first
Snowball vs. Avalanche, in plain terms
Both methods pay the minimum on every debt every month — the only difference is where your extra payment goes. Snowball sends it to whichever debt has the smallest balance, so you clear individual debts faster and get quick wins, which helps a lot of people actually stick with the plan. Avalanche sends it to whichever debt has the highest interest rate, which minimizes total interest paid — mathematically optimal, but the first payoff can take longer to arrive since you're not necessarily targeting the smallest balance.
Worked example — where the strategies actually disagree
Three debts: a $6,000 card at 24%, a $2,000 card at 8%, and a $10,000 loan at 12%, with $200 extra a month. Snowball targets the $2,000 card first (smallest balance) — done in 8 months — then the $6,000 card, then the loan, finishing debt-free in 38 months at $4,704.33 total interest. Avalanche targets the $6,000 card first (highest rate, 24%) — done in 22 months — then the loan and the small card finish together at month 37. Avalanche comes out debt-free one month sooner and saves $480.91 in interest, purely by aiming extra money at the expensive debt first instead of the smallest one.
Frequently asked questions
Which strategy actually saves more money?
Avalanche always saves the same or more in total interest than snowball, because it's mathematically targeting the debt costing you the most per month first. The gap can be small (sometimes just a few dollars, if your highest-rate debt also happens to be your smallest balance) or substantial, depending on how your specific balances and rates line up — run both to see which applies to you.
Then why would anyone choose Snowball over Avalanche?
Behavior, not math. Snowball's early wins — fully closing out a small debt in a few months — keep a lot of people motivated to stick with the plan long enough to finish. Avalanche is cheaper on paper, but if the psychological boost of clearing a debt is what keeps you consistent, snowball's real-world result can end up better than avalanche's theoretical one.
What if I don't have any extra to put toward debt?
With $0 extra, the strategy choice barely matters — both methods just pay each debt's own minimum independently, since there's nothing extra to strategically direct. The only difference comes from a paid-off debt's minimum payment rolling forward to help the next one, which is a small effect until you have at least one debt near payoff. Strategy matters in proportion to how much extra you're actually putting in.
What if my minimum payments don't cover the interest?
That's negative amortization — the balance grows every month no matter which strategy you pick, because the minimum isn't even covering what's accruing. The calculator will flag this. The fix isn't a smarter strategy, it's a larger extra payment (or negotiating a lower rate) — no ordering of minimums-only payments can dig out of a hole where the minimums themselves are losing ground.