Free debt payoff calculator. Compare the debt snowball (smallest balance first) and debt avalanche (highest interest first) methods to see which pays off faster and saves more interest.
A debt payoff calculator shows how long it takes to pay off multiple debts and how much interest you'll pay under two common strategies: the snowball method (paying extra toward the smallest balance first for psychological momentum) and the avalanche method (paying extra toward the highest interest rate first to minimize total interest paid).
55 months
Time to debt-free
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Debt Payoff Calculator
When you have several debts at once ā a credit card, a car loan, maybe a personal loan ā the order you attack them in changes both how quickly you become debt-free and how much interest you pay along the way. Paying only the minimums on everything gets you there eventually, but slowly and at maximum interest cost. Directing any extra money you have toward one debt at a time, in a deliberate order, speeds things up significantly.
The two most common approaches for choosing that order are the debt snowball and the debt avalanche. Both use the exact same total payment each month ā they only differ in which debt gets the extra money first.
Avalanche: Optimizing for Cost
The avalanche method directs all extra payment toward whichever debt has the highest interest rate, regardless of its balance. This is the mathematically optimal approach ā every dollar of extra payment reduces the balance that's costing you the most in interest, which minimizes the total interest paid across all debts by the time you're finished.
The tradeoff is psychological: if your highest-rate debt also has a large balance, it can take a long time before you fully eliminate any single debt, which some people find demotivating even though the underlying math is working in their favor.
Snowball: Optimizing for Motivation
The snowball method directs all extra payment toward whichever debt has the smallest remaining balance, regardless of its interest rate. This usually means you pay off individual debts faster in sequence ā even if one of them has a lower interest rate than another debt you're not yet targeting ā which produces a series of quick wins that many people find keeps them motivated to stick with the plan.
The tradeoff is cost: because you're not always attacking the highest-rate debt first, you'll typically pay somewhat more in total interest than the avalanche method would produce for the same extra payment amount and time period.
Limitations
This calculator assumes a fixed extra payment amount every month, applied consistently until all debts are paid off, and that minimum payments and interest rates stay constant throughout ā real-world variable-rate debts, promotional rate periods, or an extra payment amount that changes month to month will produce a different actual outcome than this projection.
It also doesn't model balance transfers, debt consolidation loans, or settlement negotiations, all of which can change the payoff math substantially. For a single-debt amortization view instead of a multi-debt strategy comparison, see our loan calculator.
Practical Use Cases
Choosing a payoff strategy
Comparing the actual time and interest cost difference between snowball and avalanche for your specific debts.
Deciding how much extra to pay
Testing how increasing your extra monthly payment shortens your time to debt-free.
Planning around a windfall
Seeing how a one-time boost to your extra payment budget accelerates payoff.
Staying motivated with a target date
Getting a concrete month count to work toward instead of an open-ended payoff timeline.
Evaluating whether to consolidate debts
Comparing your current multi-debt payoff timeline against a hypothetical single consolidated loan.
Both methods pay the minimum on every debt, then apply any extra money toward one target debt. The snowball method targets the smallest balance first, aiming to eliminate individual debts quickly for a motivating sense of progress. The avalanche method targets the highest interest rate first, which mathematically minimizes the total interest paid over the full payoff period.
Avalanche saves more money in total interest, since it always attacks the most expensive debt first. Snowball can save more in practice for some people because paying off a full debt sooner ā even a small one ā provides a motivating win that keeps momentum going. Neither is universally "better"; it depends on whether you're more motivated by minimizing cost or by quick wins.
Extra payment is any amount above the combined minimum payments across all your debts that you can consistently put toward payoff. This calculator applies that entire extra amount to one target debt at a time (chosen by your selected strategy), while every other debt still gets its minimum payment.
Yes, but usually only modestly. The avalanche method typically results in less total interest than snowball for the same extra payment amount, though the exact difference depends on your specific balances and rates ā this calculator shows you the comparison for your own numbers.
Once a targeted debt reaches zero, its minimum payment amount is freed up and gets added to the extra payment pool for the next targeted debt ā this is the "snowball" or "avalanche" effect where your payoff power grows as each debt is eliminated.