Debt Payoff Calculator
Enter your debts, add an extra monthly payment, and see the debt snowball and avalanche methods fight it out on your real numbers: payoff dates, total interest, and a winner. Instant, private, free forever.
Your debts
How to Use This Calculator
List every debt you want to attack: the balance, the APR, and the minimum monthly payment. Give each a short name so the payoff order is easy to read. Then enter the extra amount you can pay each month beyond all the minimums, and the calculator runs both strategies month by month, with interest accruing on every balance each period.
The results show a side-by-side comparison: debt-free date, total months, total interest, and total paid for each method, plus the exact order each method clears your debts and the month each one dies. Everything updates live as you type, so try different extra amounts and watch what each $50 buys you.
The Two Methods, in Plain English
Debt snowball: pay every minimum on time, then throw all extra money at the smallest balance first. When it is gone, roll its payment into the next smallest. Quick early wins keep you going.
Debt avalanche: pay every minimum on time, then throw all extra money at the highest interest rate first. When it is gone, roll its payment into the next highest rate. Mathematically this is the cheapest route, because each extra dollar prevents the most future interest.
Both methods use the exact same total monthly payment, so the comparison is apples to apples. The only difference is where the extra money goes. For the full breakdown with a worked example, read our guide to snowball vs avalanche.
Real Situations This Fits
The credit card stack: three cards with rates from 15% to 29.99%. The avalanche usually wins big here, because the rate gap is wide. But if the highest-rate card is also the biggest balance, the snowball may keep you motivated through months of no visible wins.
Mixed debt: a car loan, a personal loan, and a medical bill at 0%. The 0% debt always goes last in the avalanche (it costs nothing to carry), while the snowball might kill it early for the morale boost. Both instincts are valid; the calculator shows you the price of each.
Finding the extra payment: most people cannot name their free monthly cash on the spot. Run your numbers through our budget planner first, then bring the surplus back here as your extra payment.
The windfall question: got a tax refund or bonus? Enter it spread across the year (divide by 12 into the extra field) or compare a lump sum mentally against the monthly-extra savings. Either way, the tool shows the months shaved off.
Frequently Asked Questions
What is the difference between the debt snowball and avalanche methods?
Both methods keep you paying every minimum on time and throw all extra money at one target debt. The snowball method targets the smallest balance first for quick wins. The avalanche method targets the highest interest rate first, which costs the least in total interest. When a target debt is cleared, its payment rolls into attacking the next one.
Which is better: debt snowball or avalanche?
With identical payments, the avalanche always pays the least total interest and finishes first or tied, because killing high-rate balances first is mathematically optimal. The snowball wins on psychology: clearing a small debt fast gives an early win that keeps people going, and behavioral research finds people who focus on small balances tend to pay down more debt overall. Try both above and weigh the dollar difference against your own motivation.
When does the avalanche method win by the most?
The avalanche's advantage is largest when your interest rates are far apart, for example a 25% credit card alongside a 7% car loan. When all your rates are close together, the two methods produce nearly identical totals and the snowball's early wins cost almost nothing.
When should I pick the snowball method?
Pick snowball when you have struggled to stick with payoff plans before, when you have several small debts that can die quickly, or when your highest-rate debt is also your biggest balance and the avalanche would mean months with no visible progress. A plan you follow beats an optimal plan you quit.
What if my minimum payment doesn't cover the monthly interest?
Then the balance grows every month even though you are paying: negative amortization. The calculator flags this situation. The fix is a larger payment on that debt, an extra monthly payment directed at it, a balance transfer to a lower rate, or a hardship arrangement with the lender. Paying minimums that don't cover interest is treading water.
How much extra should I pay toward debt each month?
Whatever is left after essentials, and the calculator shows exactly what each dollar buys you in saved interest and months. Start with a number you can sustain: even $50 a month redirects thousands in interest over a payoff plan. Our free budget planner can help you find that number in your actual spending.
Does the payoff order really change the total cost?
Yes. Every dollar of extra payment does the most damage when aimed at the highest-rate balance, because it prevents the most future interest from accruing. With the same total monthly payment, the order alone can shift the payoff by months and hundreds or thousands of dollars in interest, depending on your balances and rates.
Is this debt payoff calculator free?
Yes, 100% free with no signup. All calculations happen instantly in your browser and your debts are never sent to a server.
Related tools
Snowball vs avalanche, explained in depth
How each method works, a worked example with real numbers, and when to pick each one.
Read the Payoff Guide