Debt Payoff Calculator
Enter up to five debts, choose a strategy, and see payoff timing, interest cost, and the month-by-month payoff path.
How to use this debt payoff calculator
- Enter your debts
For each debt, fill in the balance, annual interest rate, and minimum monthly payment. You can enter up to five debts.
- Add extra monthly budget
Enter any additional money you can put toward debt each month beyond the minimums.
- Choose a strategy
Select avalanche (highest rate first) or snowball (lowest balance first).
- Review the payoff plan
Check total months to payoff, total interest paid, and interest saved versus the alternative strategy.
- Compare strategies
Switch between avalanche and snowball to see which approach fits your goals for cost savings versus early motivation.
How this debt payoff calculator works
This calculator simulates paying off up to five debts using either the avalanche method (prioritizing highest interest rate) or the snowball method (prioritizing lowest balance). It shows the total payoff timeline, the first debt payoff milestone, interest cost under the selected strategy, and a month-by-month payoff schedule so you can see whether the strategy fits your motivation and cash-flow needs.
Monthly interest = balance × (rate / 12); Payment applied to principal = payment − interest A debt stack totaling $20,000 with an extra monthly budget of $200: the calculator shows how many months payoff takes, when the first debt disappears, how much total interest you pay, and how much the chosen strategy saves versus the alternative.
With $20,000 in total debt and $200 in extra monthly budget, switching from snowball to avalanche order redirects the extra payments to the highest-rate debt first. The total interest saved is typically noticeable because high-rate balances generate disproportionate interest charges every month they remain outstanding.
Adding just $50 more to the extra monthly budget on top of $200 can shave several months off the total payoff timeline. Each additional dollar applied to the target debt reduces the balance that accrues interest, and the effect compounds as freed-up minimum payments roll into the next debt in the stack.
- ✓ Minimum payments remain constant.
- ✓ When a debt is paid off, its minimum payment rolls into the next debt.
- ✓ Interest rates are fixed.
- ✓ No new charges are added to the debts.
- ✓ Minimum payments must be high enough to cover interest, or the balance will not decline.
- Avalanche is usually mathematically optimal. Snowball often delivers earlier visible wins, which can matter if motivation is the real bottleneck.
- The payoff schedule is useful for budgeting because it shows when minimum payments free up and can be rolled into the next target debt.
- If a minimum payment does not cover monthly interest, the calculator flags it because the balance would never amortize under those assumptions.
What is the debt snowball method?
The debt snowball method is a repayment strategy that targets the smallest balance first while making minimum payments on all other debts. Once the smallest debt is paid off, its minimum payment is rolled into the payment on the next-smallest balance, creating a growing payment that accelerates through the remaining debts like a snowball rolling downhill. The mathematical advantage of this approach is modest compared to the avalanche method because it does not optimize for interest cost. However, the psychological advantage can be significant: eliminating an entire debt quickly provides a tangible win that reinforces the habit of aggressive repayment. Behavioral finance research suggests that the motivation boost from early victories often outweighs the small additional interest cost. For borrowers who struggle with consistency or feel overwhelmed by multiple obligations, snowball ordering can be the difference between sticking to a plan and abandoning it.
How the avalanche method saves interest
The debt avalanche method directs all extra payment capacity to the debt with the highest interest rate, regardless of balance size. This approach minimizes total interest paid because it reduces the most expensive balance first, which is where each dollar of debt generates the most interest cost per month. Once the highest-rate debt is eliminated, the freed payment rolls to the next highest rate. The trade-off is timing: if the highest-rate debt also has a large balance, it may take many months before the first debt disappears and the psychological reward arrives. In practice, the interest savings from avalanche versus snowball depend on how different the rates are across your debts. When all rates are similar, the two strategies produce nearly identical results. When one debt carries a much higher rate than the others, avalanche can save meaningfully more. Running both strategies in this calculator and comparing the interest totals helps you decide whether the mathematical savings justify the potentially slower first payoff milestone.
Frequently asked questions
Which strategy is better?
Avalanche saves the most money in interest. Snowball gives quicker small victories. Choose what keeps you consistent.
What if I only have two debts?
Leave the unused debt fields at zero. The calculator ignores debts with zero balance.
Why does the calculator reject a minimum payment?
Because a payment that is too small to cover monthly interest means the balance will grow or never meaningfully decline. Increase the payment or lower the rate to produce a valid payoff plan.