Personal Finance
Debt Payoff Strategies
When you owe multiple debts, the order you pay them off in changes how much interest you pay in total — and the mathematically best order isn't always the one that actually works for a real person.
Definition
When someone has multiple debts at once, a debt payoff strategyis the order in which they direct any extra money — beyond each debt's minimum payment — toward paying down the balances. Two common strategies are the avalanche method (extra payments go to the highest-interest-rate debt first) and the snowball method (extra payments go to the smallest balance first).
Why this exists
Per Compound Interest, interest doesn't just apply to the original amount borrowed — it compounds on whatever balance remains, which means the same mechanism that grows a saver's balance over time also grows a borrower's balance if it isn't paid off. When someone owes multiple debts at different interest rates, every dollar of extra payment could go toward any one of them, and which one it goes toward changes how much total interest accumulates before everything is paid off.
The avalanche method directs extra payments to whichever debt has the highest interest rate, regardless of its size. Mathematically, this minimizes total interest paid, because it stops the fastest-compounding balance from growing first. The snowball method instead directs extra payments to whichever debt has the smallest balance, regardless of its rate — mathematically not optimal, but it clears entire debts faster, producing an early, visible win that can be the difference between someone staying consistent with a payoff plan and giving up partway through.
Neither method is objectively "correct" for every person, because a debt payoff plan only works if someone actually sticks with it. Avalanche saves more money on paper, assuming someone follows through until the end; snowball can save less in total interest but succeed more often in practice, because clearing a whole debt early feels different from watching a large, still-outstanding balance shrink slowly. The better strategy is whichever one someone will actually complete.
Worked example
Two debts: a $1,000 balance at 8%, and a $5,000 balance at 20%, with $200 a month available beyond minimum payments.
Avalanche: extra $200 goes to the $5,000 debt first (higher rate),
even though it's the bigger balance — takes longer to
see any single debt fully gone, but saves more interest.
Snowball: extra $200 goes to the $1,000 debt first (smaller
balance), clearing it in a few months — an early win —
before moving on to the $5,000 debt, at slightly more
total interest than avalanche.Try the Debt Payoff Calculator with your own balances, rates, and minimums to see the exact time and interest difference between the two strategies.
Try it yourself
Avalanche: months to debt-free
18
Avalanche total interest
$832.97
Snowball total interest
$1,074.22
Avalanche months
18
Snowball months
21
How the math works
Avalanche (highest rate first): 18 months, $832.97 total interest Snowball (smallest balance first): 21 months, $1,074.22 total interest
Avalanche directs every extra dollar to whichever debt has the highest interest rate; snowball directs it to whichever debt has the smallest balance. Avalanche usually saves more in total interest — here, $241.25 less — but snowball clears individual debts sooner, which can matter more in practice than the math alone.
Common misconceptions
“The avalanche method is always the right choice because it's mathematically optimal.”
It only saves more money if someone actually sticks with the plan until every debt is paid off. A technically optimal plan that gets abandoned halfway through can cost more in practice than a suboptimal plan that gets finished.
“Minimum payments alone will eventually pay off debt in a reasonable time.”
Minimum payments are often set low enough that a large share of each payment goes to interest, dragging out payoff for years and costing far more in total interest than paying any extra amount consistently.
“It doesn't matter which debt gets extra payments, as long as you're paying more than the minimum somewhere.”
Because higher-rate debt compounds faster, directing extra payments to a low-rate debt while a high-rate debt keeps growing can mean paying substantially more total interest than a deliberate avalanche or snowball order.
Also in the Glossary: Avalanche Method, Debt Payoff Strategy, Snowball Method