If you have multiple debts and want to pay the least amount of total interest possible, the debt avalanche is the mathematically optimal strategy. Here’s how it works.
How the debt avalanche works
List all your debts from highest interest rate to lowest. Pay the minimum on every debt. Put every extra dollar you can find toward the debt with the highest interest rate. When that debt is gone, roll everything you were paying on it to the next highest rate. Repeat until debt-free.
You’re eliminating the most expensive debt first — the one costing you the most money every month — and working your way down.
A real example
Say you have three debts and $200 extra per month:
- Credit card: $4,000 at 24% APR, $80 minimum
- Personal loan: $6,000 at 14% APR, $130 minimum
- Car loan: $10,000 at 7% APR, $200 minimum
Avalanche order: credit card first (24%), then personal loan (14%), then car loan (7%).
Pay $280/month on the credit card ($80 minimum + $200 extra), minimums on the others. Credit card gone in about 17 months. Roll that $280 to the personal loan — now paying $410/month on it. Gone in about 12 more months. Roll everything to the car loan — paid off in months.
Total interest paid: roughly $3,200. Compare this to paying debts in random order, which would cost about $4,800 in interest — a $1,600 difference on the same debts with the same payments.
Avalanche vs snowball: which is better
Mathematically: the avalanche saves more money every time. Psychologically: the snowball (smallest balance first) creates faster early wins that keep people motivated. Studies on debt repayment behavior show that many people who start with the mathematically optimal avalanche abandon it before finishing — while snowball users are more likely to complete their payoff journey.
Use the avalanche if you’re disciplined and motivated by numbers. Use the snowball if you need visible progress to stay on track. The best method is the one you complete.
When the avalanche makes the most difference
The higher the interest rate differential between your debts, the more the avalanche saves over the snowball. If you have a 28% credit card and a 6% student loan, targeting the credit card first saves dramatically more than the reverse. If all your debts are clustered around similar rates (10–14%), the difference between methods is smaller.