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Debt Snowball Calculator

A payoff plan across several debts — your debt-free date, and what snowball actually costs against avalanche.

Enter your debts and anything extra you can put towards them.

Debt 1
Debt 2
Debt 3

On top of the minimums. This is what shortens the plan.

Which debt first?
Estimate. A real-world figure based on the assumptions listed below, which you can change.

How this calculator works

Every month the same total goes out: all your minimum payments, plus whatever extra you add. Minimums are paid on everything, and the rest is thrown at one debt. When that debt clears, its minimum does not go back in your pocket — it rolls onto the next one. That rolling is the snowball, and it is why the last debt disappears far faster than the first.

The only question is which debt to target first. Snowball takes the smallest balance; avalanche takes the highest rate. This runs both orderings on your numbers and shows you what each costs, rather than picking one for you.

Avalanche always costs less interest, or exactly the same. That is arithmetic, not opinion — paying down the most expensive money first is cheaper by definition. What snowball buys is a cleared debt sooner, and whether that is worth paying for is a question about you rather than about the maths.

The comparison worth making first is against doing nothing extra at all. On the example below, $250 a month cuts a six-year plan to under three years and saves more than $5,000 — a far bigger difference than the choice between the two orderings.

The formula

Exactly what happens to your numbers, step by step.

  1. Each month, for every debt

    interest = balance × (APR ÷ 12)
balance  = balance + interest − payment

  2. How the money is split

    total  = sum of all minimums + extra
target = total − minimums on the other debts

    The total never changes. As debts clear, more of it lands on the target.

  3. The orderings

    snowball  = smallest balance first
avalanche = highest APR first

A worked example

A store card, a credit card and a car loan, with $250 a month to spare.

What you enter

Store card
$900 at 8.99%, $30 minimum
Credit card
$9,400 at 24.99%, $190 minimum
Car loan
$8,000 at 5.9%, $240 minimum
Extra each month
$250

The working

Total monthly payment
$460 of minimums + $250 = $710
Minimums only
66 months · $11,448 interest
Snowball
35 months · $5,948 interest · first debt gone in month 4
Avalanche
33 months · $4,030 interest · first debt gone in month 29

Avalanche saves $1,918 — snowball clears a debt 25 months sooner

This is the real trade-off, and it is smaller than the argument about it suggests. Both plans finish within two months of each other; the gap is $1,918 of interest against seeing an account closed in month four rather than month twenty-nine. Note what dwarfs both: adding $250 a month saves over $5,000 and nearly three years compared with paying minimums. The extra matters far more than the ordering.

Assumptions

Every result here rests on these. Change your inputs and the result changes with them.

  • Rates are fixed and interest is charged monthly at the APR divided by twelve.
  • Minimum payments stay at the amounts you enter for the life of the plan.
  • No new borrowing on any of these accounts.
  • Every payment is made in full and on time, so no late fees or penalty rates apply.
  • Extra money goes to the target debt in the month you have it.

What this cannot tell you

  • Real credit card minimums fall as the balance does. Entering today’s minimum makes the plan slightly conservative, which is the safer direction to be wrong in — but it means a minimums-only comparison understates how long that would really take.
  • It does not know about promotional rates. A 0% balance transfer that expires mid-plan changes the ordering completely, and this assumes today’s rate runs throughout.
  • Fees, penalty APRs and interest on new purchases are excluded.
  • It cannot tell you whether to consolidate or refinance instead. A lower rate beats any ordering, and is worth checking before committing to a plan.
  • This is arithmetic, not advice. It does not know about your emergency fund, your job security, or which of these debts is secured against your car.

Questions people ask

What is the debt snowball method?

Pay the minimum on everything and put every spare dollar into your smallest balance. When it clears, roll its payment into the next smallest, and keep going. The payment you make each month never falls — it just concentrates on fewer debts, so each one clears faster than the last.

Snowball or avalanche — which is better?

Avalanche is always cheaper, by definition, because it kills the most expensive interest first. Snowball clears individual accounts sooner. Run your own numbers above: if the interest gap is small, the faster first win may be worth more to you than the money. If it is large, that is a real cost to weigh.

How much does the difference actually come to?

Usually less than the debate implies. In the example above it is $1,918 across a three-year plan, while the two finish within two months of each other. The size of your extra payment matters far more than which ordering you choose.

Should I pay off debt or build savings first?

Compare the rates. Money earning 4% in a savings account while a card charges 25% loses you 21% a year on every dollar held back. The common exception is a small emergency fund first, so an unexpected bill does not go straight back onto the card and undo the plan.

What if a minimum payment does not cover the interest?

That debt grows while it waits its turn, and this calculator says so by name. Depending on the ordering it may still be rescued when it becomes the target — or the plan may never clear at all, in which case you get told that rather than a payoff date that does not exist.

Related calculators

Sources and review

The default figures here are typical published values, not fixed constants — densities, coverage rates and rules of thumb vary by product and by supplier. Every one of them is an input you can replace, and the figure on your supplier’s quote or the manufacturer’s data sheet beats any default. The assumptions and limitations above set out exactly what this rests on.

Methodology version 1.0.0 · Last reviewed