If you have more than one debt and some spare money each month, you have to decide which one to throw the extra at. There are two well-known methods, and the internet tends to treat the choice as a personality test. It’s actually a math question with a human footnote.
The two methods
- Avalanche. Pay the minimum on everything, and put every spare dollar at the debt with the highest interest rate. When it's gone, roll that whole payment onto the next-highest rate, and so on. This pays the least interest and clears everything soonest, because you're always attacking the most expensive debt first.
- Snowball. Pay the minimum on everything, and put every spare dollar at the smallest balance, regardless of rate. When it's gone, roll that payment onto the next smallest. This clears individual debts faster at the start, which feels good and keeps a lot of people going.
The mechanical difference is just the order. Same total payment each month, same debts, different target.
What the math says
Avalanche wins on paper, always, because it minimizes interest by definition. The question is by how much, and the answer depends on how different your interest rates are.
If your debts are all at similar rates, avalanche and snowball finish within a whisker of each other, and the snowball’s motivation is basically free. If one debt is much more expensive than the rest, say a credit card at 24 percent next to a car loan at 5 percent, avalanche can save you real money and months of payments, and paying the small cheap loan first is an expensive way to feel productive.
So the honest advice isn’t “always avalanche” or “whatever keeps you motivated”. It’s: look at the actual gap between the two for your debts. If it’s small, pick the one you’ll stick to. If it’s large, know what the snowball is costing you before you choose it.
A worked example (illustrative)
Say you have a card and a car loan, and a fixed amount spare each month. Run it both ways:
- Avalanche hits the card (higher rate) first.
- Snowball hits the smaller balance first.
A fair comparison runs each one month by month and shows you two things for each: when you’re debt-free, and how much interest you paid to get there. Seeing “avalanche clears you a few months sooner and costs a few hundred less in interest” turns the choice from a vibe into a number you can weigh against how much the early wins matter to you. (The size of that gap is entirely down to your rates and balances; there’s no universal figure.)
The lever most people miss
There’s a third dial that matters more than the method: how much extra you put in at all. Adding even a small fixed amount each month usually moves your debt-free date and your total interest more than the avalanche-vs-snowball choice does. The order matters; the amount matters more.
That’s the kind of thing worth seeing before you commit. “An extra $200 a month clears me months earlier and saves me this much interest” is a more useful fact than which method has the better reputation.
How to see it honestly
Ask a general AI assistant and it’ll explain avalanche and snowball well enough, because that part is text. Ask it to work out which is faster for your exact debts and it’ll often hand you a confident number that doesn’t survive a check. It’s predicting words, not amortizing a loan.
InvestEd does the amortizing. Put in your loans, and it runs both strategies month by month on a deterministic engine, shows you the debt-free date and the interest cost for each, and lets you see what a bit more (or less) each month does. It’ll even order the loans for you, either way, and let you override it. The assistant explains the result; the engine owns the numbers.
The short version
Avalanche costs less interest and finishes soonest. Snowball trades a little of that for early wins that keep you going. If your rates are close, pick whichever you’ll stick to. If one debt is far more expensive, know the price of the snowball before you choose it. And whichever you pick, the amount you put in matters more than the label.
Want to see it for your debts? Start a plan, add your loans, and compare the two in about a minute
