Debt Avalanche Calculator

How it works

The debt avalanche orders your debts by interest rate, highest first, and sends every spare dollar to the priciest one while the rest get minimums. When the top-rate debt clears, its full payment rolls down to the next-highest rate. Because you are always killing the most expensive interest first, this order pays the least interest of any strategy:

With the defaults, three debts of $2,000 at 26%, $6,000 at 12%, and $9,000 at 8%, totalling $17,000, with $200 extra a month, clear in about 43 months for roughly $2,943 in interest. The avalanche targets the 26% debt first, then the 12%, then the 8%. It is the cheapest route mathematically, though it can be slower to deliver a first win than the snowball.

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A worked example: three debts, avalanche order

Line up three balances the way a lot of people carry them: a $2,000 card at 26%, a $6,000 loan at 12%, and a $9,000 debt at 8%. With $200 extra to throw at them each month, the avalanche method clears all three by February 2030.

That is 43 months from now, and across the whole run you pay about $2,943 in interest on a $17,000 total balance. The order matters: you hit the 26% card first because it is the most expensive, then roll its payment onto Debt 2, then Debt 3.

Attacking the highest rate first is what keeps the interest bill low, even though that balance is the smallest. Enter your own debts and extra payment to see your debt-free date.

Make the avalanche work

• Trust the order. The highest rate may not be the smallest balance, so the first payoff can take a while. Sticking with it is what earns the lower interest bill.
• Watch for rate changes. If a card’s promotional rate expires or a variable rate jumps, its place in the order can change. Re-check when your rates move.
• Roll every cleared payment down. The saving depends on moving each freed-up minimum onto the next debt rather than absorbing it back into spending.

When the avalanche pulls ahead

The avalanche always costs the least interest, but how far it beats the snowball depends entirely on your mix of debts. Knowing what widens or narrows that gap tells you how much the patience is actually worth in your case, rather than in general.

• A wide spread between rates favors the avalanche. When one debt charges far more than the others, killing it first avoids a lot of expensive interest the snowball would leave running.
• A big balance at the top rate widens the gap the most. The larger the high-rate debt, the more you save by attacking it before anything else.
• Similar rates shrink the gap to almost nothing. If everything you owe sits within a point or two, the order barely changes the cost, and momentum becomes the better reason to choose.
• The size of your extra matters too. A larger extra clears everything faster and compresses the difference between methods; a thin extra stretches the payoff and lets the gap grow.

So before committing to the slower first payoff the avalanche sometimes asks for, look at your numbers. A steep, large balance at the top of the list makes the avalanche clearly worth it. A cluster of similar rates means you can pick either method on other grounds, because the interest difference will be small either way.