Debt Snowball Calculator
Enter your debts smallest to largest and see the exact month you become debt-free. The calculator runs the snowball method, the avalanche method, and minimum-payments-only side by side, so you can see what the popular choice actually costs you.
What the snowball method actually does
You pay the minimum on everything, then throw every spare dollar at your smallest balance — regardless of interest rate. When that debt is gone, its minimum payment joins your extra payment and rolls onto the next-smallest. The payment amount grows each time a debt disappears, which is where the name comes from.
The avalanche method is identical except you attack the highest interest rate first. Mathematically it always wins, or ties.
The comparison most calculators hide
Look at the "Avalanche saves you" output. That number is what the snowball method costs you in extra interest — and for most real debt loads it is smaller than people expect, often a few hundred dollars across several years.
That matters because the two methods do not have the same completion rate. A 2012 Journal of Marketing Research study of real repayment data found that closing accounts in order of size predicted success better than optimizing for interest. The snowball works because a debt that disappears in month 3 gives you evidence the plan is working, and evidence is what keeps people paying.
So read it this way: if avalanche saves you $2,400, take the math. If it saves you $180, take the method you will still be following in eighteen months.
Choosing your extra payment
The extra payment field is the only input you control, and it dominates everything else. Try changing it by $50 and watch the debt-free date move — the effect is non-linear, because every dollar of extra payment also compounds by freeing up minimums sooner.
Two cautions. Do not set it so high that you have no cash buffer; an unexpected car repair on a zero-balance emergency fund goes straight back onto a credit card and undoes months of progress. And check whether your card's minimum payment is a fixed dollar amount or a percentage of the balance — if it is a percentage, your required minimum falls as the balance falls, and this calculator's fixed-minimum assumption will be slightly conservative.
If the result says "never"
That means the minimum payments you entered are smaller than the monthly interest on those balances. The balance grows no matter what you pay. Check the figures, and if they are correct, this is the situation where a balance transfer or a call to a nonprofit credit counselor is the actual next step, not a repayment plan.
Frequently asked questions
Is the debt snowball or the avalanche method better?
The avalanche method always costs less in interest because it attacks the highest rate first. The snowball method has a higher completion rate in practice because eliminating a whole debt early provides visible progress. Run both in this calculator: if the interest difference is small relative to your total debt, choose the method you are more likely to finish.
How does the snowball payment grow?
When a debt reaches zero, its minimum payment does not go back into your budget — it gets added to the amount you attack the next debt with. So if you started with $200 extra and clear a card with a $25 minimum, you now have $225 hitting the next balance. Each payoff makes the next one faster.
Should I include my mortgage?
Usually not. Mortgages have long terms and comparatively low rates, and including one distorts the payoff date so much that the plan stops feeling achievable. Most people run this on credit cards, personal loans, auto loans, and student loans, then reassess the mortgage separately once those are cleared.
What if my minimum payment changes each month?
Many credit cards set the minimum as a percentage of the current balance, so it falls as you pay down. This calculator assumes a fixed minimum, which makes its estimate slightly conservative — your real payoff will be at least as fast as shown, provided you keep paying the original amount rather than the reduced minimum.
Does paying off debt this way hurt my credit score?
Paying balances down lowers your credit utilization, which generally helps. The one thing to be careful about is closing a paid-off card, since that reduces your total available credit and can shorten your average account age. Paying a card to zero and leaving it open is usually better for your score than closing it.