Debt Payoff Calculator
When you have several debts, the question is which to attack first. The two popular strategies are the snowball, which pays off the smallest balance first for quick wins, and the avalanche, which targets the highest interest rate first to minimise total interest. This debt payoff calculator runs both methods across all your debts using the same extra monthly payment, so you can compare how long each takes and how much interest each costs. You pay the minimum on every debt, then throw your extra payment at the priority debt; when it clears, its payment rolls onto the next.
Calculate
Default result: $1,763.46
Debt Payoff Calculator · Materials
calculators.dev
Total interest (selected method)
[{"balance":"2000","apr":"22","minPayment":"50"},{"balance":"2000","apr":"18","minPayment":"50"},{"balance":"8000","apr":"12","minPayment":"160"}] × snowball × 300
Shopping list
- Months to pay off
- 25
Est. total
$1,763.46
Estimate — confirm w/ supplier · calculators.dev
How the two payoff methods compare
Snowball (your selected method)
- Paid off in
- 2 yr 1 mo
- Total interest
- $1,763.46
Avalanche (for comparison)
- Paid off in
- 2 yr 1 mo
- Total interest
- $1,763.46
Both methods pay off your debts at the same time for the same total interest.
This calculator provides estimates for general informational purposes only and is not financial, investment, tax, or legal advice. Results are projections based on the figures you enter and the stated assumptions, and actual outcomes will differ. Consult a qualified financial professional before making borrowing, saving, or investment decisions.
Reviewed by the calculators.dev team · Last updated 2026-06-24
Formula reviewed against Independent public debt-payoff (snowball/avalanche) tool — total-interest and payoff-month cross-check (10-VERIFICATION.md)
How to calculate
Add each debt with its balance, APR, and minimum monthly payment, then enter the extra amount you can pay each month on top of the minimums. The calculator pays the minimums on everything and directs the extra (plus any freed-up minimums) at the priority debt — the smallest balance for snowball, the highest APR for avalanche — until every debt is gone. It reports the payoff time and total interest for both methods. For three debts totalling $12,000 with $300 extra a month, both methods finish in month 25 with about $1,763.46 in interest.
Each month: every debt accrues interest = balance × (APR ÷ 12); minimum payments are applied; the leftover payment pool (extra plus any freed minimums from cleared debts) goes entirely to the priority debt. Snowball orders debts by balance ascending; avalanche orders by APR descending. Ties are broken by the order you entered the debts. The process repeats until all balances reach zero; total interest is the sum of every month's interest across all debts.
Example calculation
Three debts — $2,000 at 22%, $2,000 at 18%, and $8,000 at 12%, with $50, $50, and $160 minimum payments — plus an extra $300 a month. The snowball method clears the smallest balances first; the avalanche method targets the highest APR first. For this set both methods pay everything off in month 25 with about $1,763.46 in total interest, because the order works out the same. When balances are tied, the debt you entered first is paid first.
- chosenTotalInterest
- $1,763.46
- chosenPayoffMonth
- 25
Assumptions
- Ties are broken by the order you entered the debts.
- APRs and minimum payments are fixed for the whole payoff; promotional rates and changing minimums are not modelled.
- The extra payment is the same every month, and freed-up minimums from cleared debts roll onto the next priority debt.
- If the minimum payments plus the extra cannot keep up with the accruing interest, the calculator reports that the plan does not pay the debt off rather than showing a misleading multi-decade schedule.
Common mistakes
- Choosing a method on feel alone. The avalanche minimises interest, but the snowball's quick wins help some people stay motivated — compare both here.
- Paying only minimums. Without the extra payment, balances with high APRs can grow faster than they shrink.
- Entering APR as a decimal (0.22) instead of a percentage (22), which understates the interest.
Frequently asked questions
What is the difference between snowball and avalanche?
The snowball pays the smallest balance first for quick psychological wins; the avalanche pays the highest APR first to minimise total interest. Avalanche usually costs less overall, but the difference can be small.
Which method saves the most money?
The avalanche method, because it eliminates the most expensive interest first. Run both here — when balances and rates line up, as in the example, the two methods can produce the same result.
How are ties handled?
When two debts have the same balance (snowball) or the same APR (avalanche), the debt you entered first is paid first. Reordering your entries changes the tie-break.
Does a bigger extra payment really help?
Yes, substantially. Every extra dollar goes straight to principal on the priority debt, shortening the payoff and cutting total interest. Increase the extra payment to see the effect.