The two orders
Snowball: smallest balance first, for quick wins that keep you going. Avalanche: highest interest rate first, which costs less in interest. When you clear a debt, its payment rolls onto the next target.
Worked example: $500 a month toward three debts
A credit card with $6,000 at 24.99% (minimum $150), a store card with $800 at 19.99% (minimum $30) and a personal loan with $3,500 at 11.9% (minimum $110). Minimums total $290, so $210 a month is extra.
Snowball: the store card is gone in month 4, the loan in month 14 and the credit card in month 27, with about $2,777 in interest. Avalanche: the credit card is gone in month 21, the store card in month 22 and the loan in month 26, with about $2,278 in interest.
Paying only the $290 in minimums would take about 58 months and cost about $6,275 in interest. Either method beats that by years.
Which to choose
If you need early wins to stick with it, the snowball's first payoff in month 4 is a real advantage. If the rates are far apart and you are disciplined, the avalanche saves money; here, about $500.
The method you keep up beats the one that looks better on paper.
Make the plan hold
Stop adding to the debts while you pay them down. Automate the minimums so nothing is late. Put windfalls, like a tax refund, on the target debt.
Try the calculator
Run your own numbers in the free debt payoff calculator. It works in your browser and nothing you enter is saved or sent.
Do it in Wrenfold
Wrenfold's debt payoff planner compares paying the highest rate first with paying the smallest balance first, and shows the month you will be debt-free. Wrenfold is the budgeting app we make. Your data stays in a file on your own device, and you can try it free in your browser with up to 60 entries.
Sources
Common questions
Does the avalanche always save money?
It saves interest whenever the rates differ, sometimes a little and sometimes a lot. When the smallest balance also has the highest rate, both methods pick the same order.
Should I save while paying off debt?
Most people keep a small emergency fund while paying debt down, so a surprise doesn't land on a credit card.
Can I switch methods partway through?
Yes. Both methods keep every minimum paid, so switching only changes which debt gets the extra money from then on.
This guide is general information, not financial, tax or legal advice. Rates, fees and rules change, so confirm current terms with the lender, store or agency involved. All dollar figures are invented examples.