There are two famous ways to order your debts when paying them off, and the internet has been arguing about them for as long as I can remember. I think the argument misses the point, but let me lay out both sides fairly first.
Avalanche: the mathematically correct answer
The avalanche method says: make minimum payments on everything, then throw every spare dollar of payment at the debt with the highest interest rate. When it's gone, move to the next highest rate, and so on.
Mathematically, the avalanche always wins. The highest-rate debt is the one costing you the most per dollar of balance, so killing it first minimises total interest. This isn't an opinion or a school of thought. It's arithmetic, and no amount of motivational framing changes it.
Snowball: the psychologically correct answer
The snowball method says: ignore the rates and attack the smallest balance first. Clear it, feel the win, then roll its payment into the next smallest, and keep going as the freed-up payments snowball.
On paper this is worse. You'll sometimes pay extra interest by leaving a high-rate debt simmering while you clear a small cheap one. But the snowball keeps winning in practice, and the reason is boringly human: finishing a debt is a visible win. One account closed, one statement that stops arriving, one bill deleted from the list. Debt payoff takes years, and people don't quit because the maths stopped working. They quit because nothing felt like progress. The snowball manufactures progress on purpose, early and often.
So the honest summary is: the avalanche wins on interest, the snowball wins on behaviour. Which one wins for you depends on which of those is your actual constraint.
The variable nobody argues about
Here's my real opinion though. The ordering debate gets all the attention, and it's the less important variable. What matters far more is the size of the payment.
Take a $15,000 debt at 18% APR. Pay $400 a month and it takes 56 months to clear, costing $7,209.95 in interest. Pay $500 a month instead and it takes 41 months and $5,077.29 of interest. That extra $100 a month saves $2,132.66 in interest, since $7,209.95 minus $5,077.29 is $2,132.66, and gets you out 15 months sooner.
Notice that's one debt, so ordering doesn't even come into it. The entire improvement came from paying more. Across a real pile of debts, the gap between snowball and avalanche is usually far smaller than the gap between "paying the minimum plus a bit" and "paying properly". People will argue for hours about which method to use, then never look for the extra $100 that would dwarf the difference.
Run your own balances through our loan payoff calculator and try a few payment levels. Watch what an extra $50 or $100 a month does to the finish date. Then, if you like, compare orderings. I'd bet the payment slider surprises you more than the method toggle does. For card debt specifically, our credit card payoff calculator does the same job with real month-by-month card compounding.
So which should you use?
If you're disciplined, avalanche. Strictly better, end of discussion. If you know you'll follow the plan for four years without needing morale boosts, take the free interest savings.
If you've started and abandoned debt payoff before, or you suspect you might, use the snowball and don't feel bad about it. A slightly more expensive plan you finish beats an optimal plan you quit in month seven. The snowball's extra interest cost is real, but it's the price of a plan that survives contact with an ordinary human being, and that's often a price worth paying.
There's also a middle path nobody markets because it doesn't have a catchy name. Snowball the first debt or two to get some early wins on the board, then switch to avalanche once the habit is established and the list is shorter. You give up a little interest at the start in exchange for momentum, then bank the maths for the long stretch. I've never seen a good argument against it beyond tidiness.
Either way, spend your energy where it counts. Pick a method in five minutes, then spend the rest of your effort finding a bigger monthly payment. That's the number doing the actual work.