Enter every debt with its balance, APR and minimum, add an extra monthly payment, and compare your payoff date and total interest under both methods
List each debt with its current balance, its interest rate (APR) and the minimum payment on the statement, then enter what you can pay on top of the minimums each month. The calculator runs the same monthly budget through two orders of attack, the avalanche (highest rate first) and the snowball (smallest balance first), and shows the debt-free date, the total interest and the month each debt disappears for both, next to what happens on minimum payments alone. Nothing you type leaves your browser.
Both methods start the same way: every debt gets its minimum payment, and every spare dollar goes to one target debt. They differ only in which debt is the target. The avalanche targets the highest interest rate, so each extra dollar stops the most expensive interest first; that is the mathematically cheapest order. The snowball targets the smallest balance, so the first debt disappears sooner and you have one fewer bill to think about. In both, when a debt is paid off its minimum payment is not spent elsewhere: it rolls onto the next target, so the amount attacking the debts grows with each payoff. That rollover is where most of the speed comes from.
Take a credit card at 24.99% ($4,200, minimum $110), a store card at 19.99% ($850, minimum $35) and a car loan at 7.9% ($9,500, minimum $275). On minimums alone, each paid separately with nothing rolled over, the last one is gone in 6 yrs 5 mo and the interest comes to $5,824. Simply keeping the total at $420 a month and rolling each freed minimum onto the next debt, with no extra money at all, finishes in 3 yrs 10 mo and saves $1,104. Every $100 added on top brings the date closer again, as the table shows.
| Extra a month | Debt-free (avalanche) | Interest (avalanche) | Interest (snowball) | Saved vs minimums (avalanche) |
|---|---|---|---|---|
| $0 (minimums rolled over) | 3 yrs 10 mo | $4,720 | $4,720 | $1,104 |
| $100 | 2 yrs 10 mo | $2,779 | $2,844 | $3,045 |
| $200 | 2 yrs 3 mo | $2,054 | $2,103 | $3,770 |
| $300 | 1 yr 11 mo | $1,660 | $1,698 | $4,164 |
| $500 | 1 yr 6 mo | $1,224 | $1,250 | $4,599 |
In the example the two methods end close together: with $200 extra the avalanche saves only $50 over the snowball, while the snowball clears the store card in month 4 rather than month 18. The rates are close enough, and the balances small enough, that the quick win is cheap. The gap opens when a small balance carries a low rate and a large one carries a high rate. With a $1,500 medical bill at 0%, a $9,000 card at 27.99% and a $6,000 loan at 11%, plus $250 extra, the avalanche costs $3,637 in interest and the snowball $5,052, a difference of $1,415; the snowball's first win comes in month 5, the avalanche's in month 23. If your smallest debt also has your highest rate, the two methods pick the same order and give exactly the same plan.
If you will follow the plan either way, choose the avalanche: it never costs more interest than the snowball and often costs less. Choose the snowball if an early win is what keeps you going; studies of real repayment data have found that people who clear whole accounts early are more likely to stick with paying down debt. The calculator shows the price of that motivation in dollars, so you can decide whether it is worth it. A middle path many people use: start with the snowball to knock out one or two tiny balances, then switch to the avalanche for the rest.
On a credit card the minimum is often little more than the month's interest plus about 1% of the balance, so most of it pays for the borrowing rather than the debt. An extra payment goes straight to principal, which shrinks next month's interest, which leaves more of the next payment for principal again. That is why the savings in the table grow faster than the extra payment does. The extra money has to come from somewhere, and the site's side-income guides and the 50/30/20 budget calculator are there to find it; the schedule below the calculator shows exactly how much of each month's payment is interest.
Interest is charged once a month at the APR divided by 12 on the balance carried into the month, and rounded to the cent, and payments are made once a month. Real statements use a daily rate and the exact days in each billing cycle, and some minimums are recalculated as the balance falls, so real figures can differ by a few dollars a month. Promotional 0% periods that end, late fees and new spending are not modelled. The plan also assumes the minimums stay at today's figure; if a card lowers its minimum as the balance falls, keep paying the old amount and the plan holds. This is a planning estimate, not financial advice; the Consumer Financial Protection Bureau publishes free guidance on managing debt and on spotting debt-relief scams.
Paying down debt raises your net worth even when income stays the same. Track both.
Both pay every minimum and put all extra money on one debt at a time. The snowball targets the smallest balance first; the avalanche targets the highest interest rate first. The avalanche always costs the same or less in interest; the snowball clears the first account sooner.
On pure math the avalanche wins, because the most expensive interest is stopped first. The snowball can still be the better choice for you if seeing accounts close quickly keeps you paying. This calculator shows the dollar difference between the two for your own debts, which is often small when your smallest debt is also your highest rate.
An extra payment goes entirely to principal, so next month's interest is lower and more of the regular payment goes to principal too. The effect compounds: on the example debts on this page, a few hundred dollars a month on top of the minimums cuts years off the payoff date and thousands off the interest.
Its minimum payment rolls onto the next debt in the order, on top of the extra you were already paying, so the monthly total you pay never drops. That growing payment is the snowball or avalanche the methods are named after.
Most planners suggest a small starter emergency fund first, often about one month of essential costs, so a surprise bill does not go back on a card. Then attack high-interest debt, then build the fuller three-to-six-month fund. The emergency fund calculator helps size it.
If a minimum is no bigger than the monthly interest, the balance cannot fall. The calculator warns when that happens; the fix is to send extra money to that debt, ask the lender for a lower rate, or look at a lower-rate consolidation loan.
Yes. Download PDF plan saves your debts, both results, the payoff order and the full month-by-month schedule. Print result prints the same page, and Save scenario keeps your numbers in this browser.
Tax rules, limits and pay data change. Check the current figures with the primary source before acting on them.