Debt Payoff Calculator
Enter your debts — balance, APR and minimum payment for each — set what you can pay a month, and see when every one clears, what the interest adds up to, and how the two standard strategies compare.
Every debt gets its minimum first each month; the rest of the budget attacks one debt at a time. When a debt clears, its minimum is not pocketed — it joins the attack on the next debt, which is what makes either method accelerate.
Formula and calculation
Worked example
Three debts — a $2,400 card at 22.9%, a $900 store card at 26.9% and a $1,200 car loan at 6.5%, with minimums of $48, $27 and $60 — clear in 10 months on a $500 monthly budget, costing $351.77 in interest under the avalanche method. Run as a snowball, the same list costs $418.38, so the avalanche saves $66.61.
Snowball or avalanche: check the math, then pick by behavior
The two methods use the same money; they differ only in which debt gets the spare dollars. Avalanche is optimal on paper — it always pays the least interest — but the edge is often small: on the sample list here it comes to about $67 over ten months, and when balances and rates are close it can be under $10. Snowball argues from a different place: a cleared debt is the progress you can see and point at, and that visible win is often what keeps a plan alive in month nine. Pick the one you will stay with. The budget field is the bigger lever either way — raising it $100 shortens the timeline more than any ordering does.
What the results mean
- Months to debt-free
- How many months until the last debt clears under the strategy you picked, with the budget you set.
- Total interest
- All the interest the whole plan pays under the selected strategy. Compare it with the other strategy's row before deciding how much the ordering really matters.
- Debt-free date
- The month of the final payment, counted from the first payment month.
- Interest, avalanche
- Total interest if every spare dollar goes to the highest-rate debt first. This is the cheaper order in the arithmetic, and the more the rates differ, the wider its lead.
- Interest, snowball
- Total interest if every spare dollar goes to the smallest balance first. It usually costs a little more in interest but retires whole debts sooner, which many people find easier to stick with.
- Saved by avalanche over snowball
- What the avalanche method saves over the snowball on this exact list. It is often smaller than people expect — behavior beats arithmetic when the gap is a few dollars a month.
Frequently asked questions
What is the difference between the snowball and avalanche methods?
Both pay every minimum and then throw all leftover money at one debt. Snowball picks the smallest balance first — visible wins, fast motivation. Avalanche picks the highest interest rate first — the least total interest, mathematically optimal. The debts clear in a different order; the budget is the same.
How do I enter my debts?
One debt per line, in the order: name, balance, APR, minimum payment. For example: “Visa, 2400, 22.9, 48”. Use plain numbers with no commas or dollar signs; if a line is malformed the calculator tells you which line and what it expected.
Why do the two strategies cost nearly the same?
The difference grows with how much the rates differ and how long the debt lives. When one rate towers over the rest — a 26.9% store card beside a 6.5% car loan — avalanche pulls ahead. When rates are close and the budget clears everything within a year, the ordering barely matters, which is the case on the sample three-debt list.
Does the budget have to cover the minimum payments?
Yes. A budget below the total minimums cannot be applied — issuers require the minimums first — so the calculator asks you to raise the budget to at least their sum. If that is impossible, the numbers to attack first are the minimums themselves: a consolidation loan or a negotiated lower rate changes the input that matters.