Debt Snowball vs Avalanche Calculator
Enter each debt and any extra you can add each month. The calculator runs both payoff orders month by month and shows how long each one takes and how much interest each one adds up to.
How to use it
This calculator compares two common ways to order your extra payments. Snowball puts any money beyond the minimums toward the smallest balance first. Avalanche puts it toward the highest APR first. Both orders pay every minimum, every month. Only the order of the extra money changes.
1. List your debts
Add one row per debt. For each one, type:
- Balance: what you owe today. A recent statement is a good source.
- APR (%): the yearly interest rate on that debt. Type 0 for a debt with no interest, such as many medical bills.
- Minimum payment: the smallest monthly payment the lender asks for.
Use + Add a debt for more rows and the × button to remove one. Rows with a balance of 0 are left out.
2. Add an extra monthly amount
Extra payment each month is anything you plan to pay on top of all the minimums combined. It can be 0. The calculator adds your minimums and the extra together and shows the result as your monthly payment budget. That total stays the same every month, so when one debt is paid off, its minimum moves on to the next target debt instead of disappearing.
3. Read the two results
For each order you'll see:
- Debt-free in: the number of months until every balance reaches $0.
- Total interest: all the interest added across every debt.
- Total paid: what you'd pay in total, balances plus interest.
- Payoff order: which debt is paid off in which month.
A line under the results sums up the difference in interest and months between the two orders.
How the math works
Each month, every open debt adds interest equal to its balance × APR ÷ 12, rounded to the cent. Then each debt gets its minimum payment (or its whole balance, if that's smaller). Whatever is left of the monthly budget goes to the target debt. For snowball, the target is the smallest balance (if two balances tie, the higher APR goes first). For avalanche, the target is the highest APR (if two APRs tie, the smaller balance goes first). If the target is paid off partway through a month, the rest flows to the next debt in line.
The calculator stops at 600 months (50 years). If a minimum payment doesn't cover the first month's interest on that debt, you'll see a warning, because at that payment the balance grows.
Keep in mind
This is an estimate. Many lenders calculate interest daily, charge fees, or change rates, so your statements won't match these numbers exactly. The tool doesn't model 0% promo periods, lump-sum payments or new charges. Which order fits you depends on more than the math, such as how much an early win matters to you, so treat the results as a comparison to learn from, not a recommendation.
Worked example
These are the numbers loaded by Try an example:
- Store card: $600 balance, 26.99% APR, $30 minimum
- Credit card: $3,200 balance, 22.9% APR, $90 minimum
- Car loan: $8,400 balance, 6.5% APR, $260 minimum
- Medical bill: $450 balance, 0% APR, $50 minimum
- Extra payment each month: $200
The minimums add up to $430, so the monthly payment budget is $630.
Snowball pays off the medical bill in month 2, the store card in month 4, the credit card in month 14 and the car loan in month 23. Debt-free in 23 months, with $1,236.77 in total interest and $13,886.77 paid in total.
Avalanche pays off the store card in month 3, the medical bill in month 9 (its own $50 minimum clears it), the credit card in month 13 and the car loan in month 22. Debt-free in 22 months, with $1,195.23 in total interest and $13,845.23 paid in total.
With these numbers, avalanche adds $41.54 less interest and finishes 1 month sooner. Snowball clears its first debt a month earlier (month 2 instead of month 3). Your own numbers can show a bigger gap, a smaller one, or none.
FAQ
Why don't these numbers match my statement?
The calculator adds interest once a month at APR ÷ 12. Many lenders calculate interest daily and may add fees, so real balances drift a little from this estimate.
What happens when one debt is paid off?
Its minimum payment stays in your monthly budget and goes to the next target debt. That's why the total monthly payment never drops while debts remain.
Can I enter a 0% debt?
Yes. Type 0 as the APR. The tool doesn't handle a promo rate that ends partway through, so for a promo balance it treats 0% as permanent.
What does the warning about interest mean?
It appears when a debt's minimum payment is the same as or less than its first month's interest. At that payment the balance doesn't go down on its own.
Is my information saved?
No. Nothing you type is stored by the site or sent anywhere; the calculator runs in your browser and clears the form each time the page loads.