Estimates assume fixed APRs and payments on time. This is a calculator, not financial advice.
Leave the APR empty for a debt with no interest. Amounts can have cents, like 1240.50. It starts with an example of four debts, and it keeps your numbers in this browser only, so they're still there next time.
Snowball or avalanche?
Both methods pay the minimum on every debt each month, and both put your extra money on one debt at a time. They only differ in which debt gets the extra first.
- Snowball pays the smallest balance first. If two balances are equal, the one with the higher APR goes first.
- Avalanche pays the highest APR first. If two APRs are equal, the smaller balance goes first.
Once a debt is paid off, its payment moves to the next debt in line. Your total payment stays the same every month, so the amount going at the target keeps growing. That's the snowball part, and avalanche works the same way.
A worked example
Here are four debts with $480 of minimums a month, plus $150 extra, so $630 a month in total. The first payment is in December 2026.
| Debt | Balance | APR | Minimum |
|---|---|---|---|
| Store card | $1,240 | 24.9% | $40 |
| Student loan | $3,450 | 4.5% | $60 |
| Visa | $4,860 | 21.5% | $120 |
| Car loan | $8,900 | 6.9% | $260 |
With the snowball, you're debt free in October 2029, after 35 months, and pay $3,413 in interest. With the avalanche, it's September 2029, after 34 months, and $2,803 in interest. So in this example the avalanche saves $610 and one month.
| # | Snowball | Paid off | Avalanche | Paid off |
|---|---|---|---|---|
| 1 | Store card | July 2027 | Store card | July 2027 |
| 2 | Student loan | July 2028 | Visa | December 2028 |
| 3 | Visa | August 2029 | Car loan | June 2029 |
| 4 | Car loan | October 2029 | Student loan | September 2029 |
The store card goes first either way, since it's the smallest balance and also the highest APR. After that the two plans split. Next, the snowball clears the student loan in July 2028, while the avalanche goes after the Visa at 21.5% and clears it in December 2028. The student loan, at 4.5%, waits until last.
Paying only the minimums, $480 a month with no extra, you'd be debt free in January 2031, after 50 months, with $5,405 in interest. The extra $150 a month is what makes the big difference here, more than the choice of method.
Which one should you pick?
Avalanche usually costs less interest, because the extra money goes to the most expensive debt first. The snowball often clears its first debt sooner, when your smallest debt isn't your most expensive one, and some people find that small win keeps them going.
Put your own numbers in and look at the gap. A big saving from the avalanche is worth knowing about. When the two are a few dollars apart, pick the one you think you'll stick with.
When a minimum doesn't cover the interest
If a debt's minimum payment is less than one month of its interest, the balance grows each month instead of shrinking. You'll see a minimum payment warning for that debt. With enough extra money the plan can still finish, because that debt grows until it becomes the target and then gets paid down. And if your whole monthly payment can't get ahead of the interest, you'll see No payoff date instead of a made up one.
How the math works
- Each month, every debt adds interest of its balance times its APR divided by 12, rounded to the cent.
- Every debt gets its minimum payment, or whatever's left of it if that's less.
- The rest of your monthly payment goes to the target. A target that's paid off partway through the month passes the rest to the next debt in the same month.
- The order is set from today's balances and doesn't change along the way.
Real lenders can count interest by the day, change rates, add fees or end a 0% offer, so your statements may differ a little. Plans longer than 50 years show no payoff date.
Questions
Is the debt snowball or avalanche faster?
The avalanche usually finishes at the same time or a little sooner, and pays less interest. In the example above it's one month sooner and $610 cheaper. Its first paid off debt often comes sooner with the snowball.
What happens to a payment when a debt is paid off?
It moves to the next debt in line. Your total payment each month stays the same until everything is paid off, so the last debts get paid off faster.
Do I need to pay extra for this to work?
No, but it helps. With no extra, the calculator still rolls each paid off minimum into the next debt. Compare that with the minimums only line under the results.
Is this financial advice?
No. It's a calculator that runs your numbers under simple, fixed assumptions. For advice on your situation, talk to a qualified adviser or a nonprofit credit counselor.
Is there an app for this?
I'm finishing a debt payoff planner for Android with the same math, a month by month schedule for every debt and saved plans. It isn't out yet. When it is, you'll find it on my apps page.