Debt Payoff Calculator

Snowball vs avalanche: two ways to get debt-free

Both strategies pay every debt its minimum each month and then throw all of your spare cash at one target debt. They differ only in which debt they target first. The avalanche method targets the debt with the highest APR, so you eliminate your most expensive interest first—mathematically, this always pays the least total interest. The snowball method targets the smallest balance first, clearing whole debts quickly to build motivation.

How the calculator works

For each month, for each debt:
  interest  = balance × (APR ÷ 12 ÷ 100)
  balance   = balance + interest − payment

  1. Pay every debt its minimum payment.
  2. Apply the leftover budget (your extra +
     freed-up payments) to the target debt:
       avalanche → highest APR first
       snowball  → smallest balance first
  3. When a debt reaches 0, roll its payment
     into the next target (the "rollover").
Repeat until every balance is 0.

Your total monthly budget stays constant—the sum of every minimum plus your extra payment. As each debt clears, that money cascades onto the next one, which is why payoff speeds up the further you go.

When each method wins

• Avalanche wins on pure cost. If your highest-APR debt is also large, the interest savings can be substantial.
• Snowball wins on momentum. Knocking out a full debt in the first month or two is a real psychological boost, and people who stay motivated finish more often.
• When the interest difference is small, pick the method you will actually stick with—consistency beats optimization.

Why minimum-only payments trap you

On a high-APR balance, the minimum payment can be barely more than the monthly interest. Most of each payment goes to the lender, principal barely moves, and the debt lingers for years. Even a modest extra payment changes the math dramatically, because every extra dollar attacks principal directly and removes all the future interest that dollar would have accrued.