Debt Snowball Calculator guide
List your debts, add an extra monthly payment, and compare the snowball and avalanche methods side by side with a month-by-month payoff schedule.
How the debt snowball works
List every debt. Pay the minimum on all of them. Throw every extra dollar at the smallest balance. When it is gone, take its whole payment (minimum plus extra) and add it to the next-smallest debt. Each payoff makes the next payment bigger, which is the snowball.
The key rule, and the one most people break: your total monthly debt budget never goes down. When a card hits zero, that $35 minimum does not go back into your spending. It rolls forward. This calculator holds the budget fixed at all your minimums plus your extra payment and simulates every month until the last balance is zero.
The math each month: interest = balance × APR ÷ 12 for every debt, then minimums on everything, then whatever is left of the budget goes to the current target. If a target is paid off mid-month, the leftover spills into the next target the same month.
Snowball vs avalanche
The only difference is the order. Snowball targets the smallest balance first. Avalanche targets the highest interest rate first. Avalanche is mathematically optimal: it always costs the same or less interest, because every extra dollar kills the most expensive debt. Snowball wins on behavior: you close accounts sooner, and seeing a balance hit zero in month 4 keeps people going. Research by Gal and McShane (Journal of Marketing Research, 2012) found that consumers who closed out individual accounts were more likely to eliminate their total debt.
Pick avalanche if the interest gap is large and you trust your discipline. Pick snowball if you have tried and quit before. Either one beats paying minimums. Toggle both above and look at the real dollar difference for your debts before you decide; often it is smaller than people expect.
Worked example: four debts, $250 extra a month
Store card $900 at 18.99 percent ($35 minimum), personal loan $3,000 at 11.99 percent ($100), credit card $7,500 at 27.99 percent ($225), car loan $12,000 at 7.5 percent ($320). Minimums total $680; with $250 extra the budget is $930 a month.
Snowball: store card gone in month 4, personal loan in month 11, credit card in month 25, car loan in month 31. Total interest: $4,752.
Avalanche: the credit card goes first in month 20, then the store card in month 21, the personal loan in month 24, and the car loan in month 30. Total interest: $4,142. Avalanche saves $610 and one month here, because the biggest balance also carries the highest rate. But snowball gives you a win in month 4, while avalanche's first payoff takes 20 months.
Drop the $250 extra and just roll the minimums forward: 48 months and $8,677 of interest. The extra $250 a month cuts 17 months and roughly $3,900 of interest. The extra payment matters more than the method.
Mistakes that stall a payoff plan
Spending freed-up minimums. The snowball only works if the total payment stays the same. Automate it.
Adding new debt. Paying off a card and then running it back up resets the clock. Freeze the card, not the account; closing old accounts can lower your credit score by shortening your credit history.
Skipping a small emergency fund. Without $1,000 to $2,000 in cash, the first flat tire goes on a credit card.
Ignoring 0 percent promos. A balance transfer card at 0 percent for 18 months with a 3 to 5 percent fee can beat both methods for high-APR card debt, if you pay it off before the promo ends.
Treating a mortgage like consumer debt. Most snowball plans exclude the mortgage; its rate is usually lower and the balance would stall the plan for decades.
Your list stays on your device
The debt list saves in your browser's local storage, not on a server. Come back next month, update the balances from your statements, and see the new debt-free date. Nothing to sign up for. Clearing your browser data or using a private window resets it.
How we calculate: sources
Frequently asked questions
How does the debt snowball method work?
Pay minimums on every debt and put all extra money toward the smallest balance. When it is paid off, roll its full payment into the next smallest. Your total monthly payment stays the same until everything is gone.
What is the difference between debt snowball and debt avalanche?
Snowball pays the smallest balance first. Avalanche pays the highest interest rate first. Avalanche always costs the same or less interest; snowball gives faster early wins.
Which is better, snowball or avalanche?
Avalanche saves the most money. Snowball helps many people stay motivated. Use the toggle to see the actual difference for your debts, which is often a few hundred dollars.
How much extra should I pay each month?
Any amount helps, and it matters more than the method. In the example on this page, an extra $250 a month cuts the payoff by 17 months and saves about $3,900 of interest.
Should I include my mortgage?
Most plans cover consumer debts only, such as credit cards, car loans, and personal and student loans. A mortgage's low rate and long term would stall the snowball.
Why does the calculator say my debt never gets paid off?
Your payments do not exceed the interest being charged. Raise the extra payment or the minimums until the balance falls each month.
Is my debt list saved or uploaded?
Everything runs in your browser. Nothing you enter is uploaded to a server or stored by us. The list is kept in this browser's local storage so it is there when you come back.
Is the debt snowball or avalanche better?
Avalanche always costs the same or less interest. Snowball pays off accounts sooner, which helps many people stick with the plan. Compare both for your debts with the toggle; the gap is often a few hundred dollars.
Should I include my mortgage in the debt snowball?
Usually not. Most plans cover consumer debt only: credit cards, car loans, personal and student loans. A mortgage's lower rate and long term would stall the snowball.