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Debt snowball & avalanche calculator
List each debt with its balance, interest rate and minimum payment, add the extra amount you can put toward debt each month, and see how long payoff takes and how much interest you pay under both methods. The two rarely differ by more than a few months; the interest difference is what surprises people.
Your debts
Snowball versus avalanche, in one paragraph each
Snowball pays minimums on everything and sends every spare dollar at the smallest balance. When that debt closes, its minimum payment rolls onto the next smallest. You clear whole accounts early, which is why it works for people who need to see progress to keep going.
Avalanche pays minimums on everything and sends every spare dollar at the highest interest rate. It is mathematically the cheapest route out: every dollar aimed at the most expensive debt saves more interest than it would anywhere else. The first account can take a long time to close, which is where some people lose momentum.
How the calculator simulates payoff
- Each month, every open debt is charged one month of interest: balance × APR ÷ 12.
- Minimum payments go out on every debt first.
- The extra amount, plus the minimums freed up by any debt already paid off, goes to the target debt: smallest balance for snowball, highest APR for avalanche.
- The month a debt reaches zero, its minimum joins the extra from the next month on. That rollover is the "snowball" in the name and is what makes payoff accelerate.
- If minimums do not cover the interest, the tool says so rather than showing a payoff date it cannot support.
Which one should you choose?
| Choose snowball if… | Choose avalanche if… |
|---|---|
| You have tried before and stalled. | The interest gap between your debts is large (a 24% card next to a 6% loan). |
| Several small balances are cluttering your month. | You are motivated by the total cost, not the account count. |
| The interest difference above is small. | The interest difference above is hundreds or thousands. |
A common compromise: snowball the first one or two tiny balances to clear the clutter, then switch to avalanche for the rest. Whichever you pick, the extra payment matters more than the order. Doubling the extra shortens the timeline far more than choosing the perfect sequence.
Where the extra payment comes from
The extra is the number that moves the result, so it is worth finding. Two places to look: the subscription cost calculator turns up recurring charges people forgot they had, and the 50/30/20 split shows whether wants are crowding out the debt line. Even fifty dollars a month, applied consistently, changes the date on the result above.
Frequently asked questions
Does the calculator handle 0% promotional rates?
Enter the promotional rate as the APR and it will be treated as fixed for the whole payoff. It does not model a promo expiring on a date; a full payoff tracker with promo-expiry handling does that, and the one in the shop rebuilds the plan when the rate changes.
Why does it say my minimums do not keep up with the interest?
On one or more debts, a month of interest is larger than the minimum payment, so the balance grows even while you pay. Raise the extra amount, or call the lender: a lower rate or a hardship plan changes that arithmetic quickly.
Should I consolidate instead?
Consolidation only helps if the new rate is lower than the debts it replaces and you stop using the cards it clears. Run the calculator with the consolidated loan as a single line, at its real rate, and compare the total interest with the result for your current debts.
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Keep the plan honest month after month
The Debt Payoff Tracker compares four payoff orders on the same numbers, handles promo expiries and percent minimums, and reconciles each month against your real statements so the forecast rebuilds from reality.