There are two well-known ways to clear multiple debts, and they disagree about which one to attack first. One is mathematically optimal. The other is behaviourally superior. Choosing correctly matters more than most advice admits, because the best method is worth nothing if you abandon it in month four.
The two methods
Avalanche: highest interest rate first
Pay the minimum on every debt, then throw all spare money at whichever debt carries the highest interest rate. When that one is gone, move to the next highest, and so on.
This minimises the total interest you pay. It is the mathematically correct answer to "how do I pay the least?"
Snowball: smallest balance first
Pay the minimum on every debt, then throw all spare money at whichever debt has the smallest balance, regardless of its rate. Clear it. Roll that payment onto the next smallest.
This produces a quick, visible win — often within weeks — and then a growing "snowball" of freed-up payment money as each debt falls.
The same spare money, aimed in two different directions.
What the research says
A well-known study from Northwestern University's Kellogg School found that borrowers who focused on smaller balances were more likely to eliminate a debt entirely and stayed more engaged with their repayment. Follow-up work has repeatedly found the same pattern: the psychological reward of closing an account drives persistence, and persistence is what clears debt.
This is not a quirk of a single study. It reflects a basic fact about human motivation. Progress you can see creates momentum. Progress you cannot see feels like nothing is happening.
The finding that matters: the avalanche wins on paper, but the snowball wins on finishing. Since an unfinished plan saves exactly nothing, the "less efficient" method can deliver the better real-world outcome.
The actual difference in money
The size of the gap depends on how spread out your interest rates are. Here is a worked example.
| Debt | Balance | Rate | Minimum |
|---|---|---|---|
| Credit card | $2,400 | 22.9% | $60 |
| Store card | $900 | 26.5% | $30 |
| Personal loan | $6,800 | 12.4% | $180 |
| Spare money available per month | $250 | ||
Avalanche attacks the store card first (highest rate at 26.5%), then the credit card, then the loan. Snowball attacks the store card first (smallest balance at $900), then the credit card, then the loan.
In this particular case, both methods start with the same debt — because the smallest balance also has the highest rate. That is more common than people expect, which is part of why the two methods often produce similar results.
When the gap widens is when you owe a lot at a low rate and a little at a high rate. Then the avalanche can save several hundred over a year, while the snowball generates a fast win that keeps you going.
Rough rule
- Rates within a few points of each other: use the snowball. The interest difference is small and the motivation gain is large.
- One debt far more expensive than the rest: use the avalanche. The interest saving is worth being patient for.
- Spotty track record with past attempts: use the snowball. Completion beats optimisation.
Model your own payoffEnter a balance, rate and payment to see your debt-free date — then add an extra payment and watch it move.
Open the debt calculatorWhat both methods require
Whichever you choose, the mechanics are identical. These four steps matter more than the ordering decision.
- List every debt with its balance, rate and minimum payment. You cannot attack what you cannot see.
- Pay every minimum, every month. Missing one damages your credit and adds penalties — both of which make the debt more expensive.
- Find your spare money. The difference between the minimums and what you can actually pay is the entire engine of both methods. Without it, neither works.
- Roll the payment forward. When one debt clears, its payment joins the attack on the next. This is the "snowball" effect, and it is why the last debt falls so fast.
The mistake that defeats both
The most common failure is not choosing the wrong method. It is treating the freed-up payment as spare cash once a debt clears.
If you clear a $60 minimum payment and absorb it into your general spending, the snowball never accelerates and the avalanche loses its compounding advantage. The cleared payment must go somewhere productive — into the next debt, or into savings you will not touch.
Protect your buffer. Before you throw every spare pound at debt, make sure you have a small emergency fund. Without one, an unexpected bill goes straight onto a credit card and you are back where you started.
Frequently asked questions
Which saves more money, avalanche or snowball?
The avalanche always saves at least as much in interest, since it targets the most expensive debt first. The difference is often modest unless your rates vary widely.
Which method do people actually finish?
Research points to the snowball for higher completion rates, because clearing a debt early delivers a visible motivational win.
Should I still pay minimums on other debts?
Always. Pay at least the minimum on every debt to avoid penalties and credit damage, and direct all remaining spare money at the single target debt.
What if I can only afford the minimums?
Then focus on reducing expenses or increasing income first. Neither method generates progress without spare money above the minimums. If even the minimums are unaffordable, speak to a free debt advice service.
Sources and verification
Everything on this page that could be checked was checked against the primary sources below — regulators and government agencies rather than summaries of them. Where a figure is an illustrative example rather than a quoted statistic, the page says so.
- Debt collection: your rights and how the Debt Collection Rule worksConsumer Financial Protection Bureau (US)
- What is the difference between a credit counsellor and a debt settlement company?Consumer Financial Protection Bureau (US)
- Credit and loansFederal Trade Commission (US)
Last reviewed by Mohamed Elnhas. If you find an error on this page, tell us — corrections are made to the page and noted, not quietly removed.