Debt payoff calculator: snowball vs avalanche

Last checked August 6, 2026

Two methods, one arithmetic difference, and an enormous amount of internet argument that mostly obscures how small the gap usually is.

This page works a real example all the way through so you can see both methods' math side by side. It does not tell you which method to use, because on most real debt sets the difference is smaller than the difference between following a plan and abandoning one.

The methods

Both start the same way. You pay the minimum on every debt, then put every spare dollar at one target debt until it clears. When it clears, its whole payment rolls into the next target. That rolling payment is why either method accelerates: your total monthly payment stays flat while the amount going to principal climbs.

They differ only in how you pick the target.

Avalanche targets the highest APR first. This is mathematically optimal. Given a fixed monthly budget, no ordering pays less total interest, and none finishes sooner.

Snowball targets the smallest balance first. This clears individual accounts faster, which some people find easier to sustain.

That is the whole distinction. Everything else written about these methods is commentary on that one choice.

A fully worked example

Three cards, $14,000 total. The balances and rates are deliberately arranged so the two methods disagree, which is the only case where the comparison is interesting.

Minimums total $355. Assume a total budget of $555 a month, so $200 above the minimums.

Representative example. For a $5,000 loan at a 10% APR over 36 months, the monthly repayment would be $161.34. Over the term, the total repayment would amount to $5,808.24, with $808.24 in interest. Loan terms range from 6 months to 12 years, with APRs between 5.99% and 35.99%. The exact rate you receive depends on factors like your creditworthiness, loan size, and repayment schedule.

Snowball order by balance ascending: A, B, C. Avalanche order by APR descending: B, C, A.

The engine

Both are simulated the same way, one month at a time:

1. Accrue one month of interest on each balance: interest = balance * APR / 12.
2. Pay the minimum on every debt except the current target.
3. Put the entire remaining budget at the target.
4. When a debt hits zero, its payment rolls into the next target.
5. Repeat until every balance is zero, summing interest as you go.

Month-by-month simulation, not a closed-form formula. The rolling payments and the changing target make a shortcut wrong.

The results

Avalanche saves $216.53 and one month. On $14,000 of debt over three years, that is a difference of about 1.1% of the total amount paid, or roughly $6 a month.

That number is the honest headline of this page, and it is why we are not going to advocate for either method. Avalanche is genuinely better. It is better by an amount that is easily swamped by whether you actually stick to the plan.

Look at the other row, though, because it is where the real trade-off lives. Under snowball, the first account disappears at month 6. Under avalanche, nothing disappears until month 19. Thirteen months of no visible progress is a real thing to ask of yourself, and it is the reason snowball exists.

When the gap gets large

The $216.53 gap is not universal. It widens sharply when:

• The highest-rate debt is also the largest. A big balance at 29.99% left sitting while you clear small cheap accounts compounds expensively.
• The APR spread is wide. Three cards between 18% and 27% produce a small gap. A payday-type product at 100%+ alongside a card at 15% produces an enormous one.
• The timeline is long. Five years of misordering costs meaningfully more than three.

And it narrows to almost nothing when balances are similar, or when the smallest debt happens to also be the most expensive, in which case both methods pick the same order and the question does not arise.

Representative example. For a $5,000 loan at a 10% APR over 36 months, the monthly repayment would be $161.34. Over the term, the total repayment would amount to $5,808.24, with $808.24 in interest. Loan terms range from 6 months to 12 years, with APRs between 5.99% and 35.99%. The exact rate you receive depends on factors like your creditworthiness, loan size, and repayment schedule.

The things the calculator cannot model

New spending. Every projection here assumes you add nothing. That assumption is wrong more often than any interest rate on the page. If the cards keep getting used, neither method finishes.

Declining minimums. Card minimums typically fall as the balance falls. Paying the declining minimum stretches real payoff well past what this projects. The tool holds them constant, which is the standard convention and slightly optimistic.

Variable rates. Card APRs move. A projection built on today's rate is a projection.

Whether you will keep going. Thirty-five months is a long time. The method that finishes fastest on paper is not the fastest method if you stop at month 14. That is not an argument for snowball. It is a reason to be honest with yourself about which schedule you will actually follow, and to pick accordingly.

If neither plan gets you there

If the calculator returns a payoff date you cannot live with, or no payoff date at all, the answer is not a different ordering.

The FTC notes you can negotiate directly with creditors yourself rather than paying a company to do it. The CFPB points to nonprofit consumer credit counseling, which can work with you and your creditors on a debt management plan you can afford, and usually helps with a budget as well. The CFPB also warns that debt settlement companies often charge expensive fees, typically encourage you to stop paying your credit card bills, and may leave you deeper in debt than when you started.

A consolidation loan is one option among several, and only worth it if the rate and fee together beat what you are already doing. Run that comparison before assuming it helps.

Sources

• Loans Generator, Loan Agreement Overview (live site APR disclosure and representative example), accessed August 6, 2026.
• Consumer Financial Protection Bureau, What is a debt relief program and how do I know if I should use one?, accessed August 6, 2026.
• Federal Trade Commission, How To Get Out of Debt, accessed August 6, 2026.