General Finance
Debt Payoff Calculator (Snowball vs. Avalanche)
Enter up to five debts and any extra you can put toward them each month. The calculator runs both the snowball and the avalanche order and shows the payoff date, total interest, and the order each debt clears.
Calculation inputs
Leave a debt's balance blank or zero to skip it. Minimum payments must cover monthly interest.
Results
No result yet
Complete the fields and select Calculate to show results here.
Estimates only. Actual payoff depends on your lender's terms, fees, and payment timing.
About this calculator
This calculator compares two common strategies for paying off multiple debts — the snowball method and the avalanche method — using up to five balances, rates, and minimum payments. It's built for anyone juggling several loans or cards who wants to see when each one clears and how much interest each plan costs.
How the calculation works
- Each month every debt accrues interest at balance × rate ÷ 12
- Minimum payments are paid on every debt first
- The extra payment, plus the minimums freed by cleared debts, goes to the target debt
- Snowball targets the smallest balance first; avalanche targets the highest rate first
Notes and assumptions
If a minimum payment does not cover the monthly interest, that debt never clears and the projection stops at 50 years.
The payoff dates assume payments start this month and never miss.
How it works in plain English
You list each debt's balance, interest rate, and minimum payment, plus any extra amount you can put toward debt every month beyond the minimums. The calculator then simulates both strategies month by month: each debt accrues interest on its remaining balance, minimum payments are made on everything, and the extra payment is funneled to one target debt at a time.
The snowball method targets the smallest remaining balance first, regardless of interest rate, which clears individual debts faster and can help with motivation. The avalanche method targets the highest interest rate first, which generally minimizes total interest paid over the full payoff period.
As each targeted debt is paid off, its minimum payment is freed up and added to the extra payment pool, so the amount attacking the next debt grows over time — this is the 'snowball' or 'avalanche' effect. The calculator reports the payoff date and total interest for both strategies side by side, along with the month each individual debt is cleared.
The formula
- Each month: interest accrued = remaining balance x (annual rate / 12)
- Minimum payments are made on every debt first
- Extra payment plus freed-up minimums goes to the current target debt
- Snowball order: smallest balance first; Avalanche order: highest rate first
Worked example
Say you have three debts: $1,200 at 22% with a $45 minimum, $4,800 at 18% with a $120 minimum, and $9,500 at 7.5% with a $190 minimum, and you can put $300 extra toward debt each month.
Under the avalanche method, the extra payment first attacks the 22% card since it has the highest rate, clearing it in a few months. Once cleared, its $45 minimum joins the extra payment against the 18% card, and so on. The avalanche approach typically finishes with less total interest paid than the snowball approach, though the snowball method (starting with the $1,200 balance, which is also smallest here) clears a debt just as quickly in this particular case.
Frequently asked questions
Which strategy saves more money, snowball or avalanche?
The avalanche method — paying extra toward the highest interest rate first — generally results in less total interest paid, because it reduces the balance that's growing fastest. The snowball method, targeting the smallest balance first, often costs a bit more in interest but can build momentum through quicker wins.
What if a minimum payment doesn't cover the monthly interest?
If a debt's minimum payment is smaller than the interest it accrues each month, that balance will never shrink under either plan, and the calculator's projection stops after 50 years without a payoff. In that case the minimum payment needs to increase, or the extra payment needs to be redirected there first.
Does the calculator assume payments never change or get missed?
Yes. Both projections assume you pay the same total amount every month without interruption, starting immediately. Missed payments, changing interest rates, or additional charges to the cards would extend the actual payoff timeline beyond what's shown here.
Can I compare fewer than five debts?
Yes. Any debt fields left blank or at zero are simply skipped in the simulation, so you can enter just one, two, or any number up to five debts and the calculator will only include the ones you fill in.
Does paying extra toward one debt affect the minimums on the others?
No, minimum payments on every other debt stay the same and are always paid in full each month regardless of strategy. Only the leftover extra amount is directed toward whichever single debt the chosen method is currently targeting.
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