Debt snowball vs avalanche calculator
List your debts with balances, interest rates and minimum payments, then add any extra you can pay each month. The calculator runs both strategies side by side.
How it works
Both methods pay the minimum on every debt and put every spare pound or dollar on one target debt. When a debt is cleared, its minimum payment rolls into the next target, so the amount aimed at debt never shrinks.
The avalanche targets the highest interest rate first, which always costs the same or less in interest. The snowball targets the smallest balance first, which gives quicker wins and can help you stick with the plan. The gap between them is often small, so the best plan is the one you will keep to.
The formula
Each month: add balance × APR/12 interest to every debt, pay every minimum, then send the rest of the fixed monthly budget (sum of minimums + extra) to the target debt. Snowball sorts targets by balance (smallest first); avalanche sorts by APR (highest first).
Worked example
Three debts: Card A $1,000 at 20% (min $50), Loan B $3,000 at 10% (min $75) and Card C $2,000 at 25% (min $60), plus $100 extra, for a $285 monthly budget. Both methods finish in 25 months. The avalanche costs $977.30 in interest and the snowball $1,016.89, so the avalanche saves about $40, while the snowball clears its first debt in month 8.
Frequently asked questions
Which method is mathematically best?
The avalanche never costs more interest than the snowball when the monthly budget is the same. The snowball can still be the better choice if early wins keep you motivated.
Should I include my mortgage?
Usually not. These methods are designed for consumer debts like cards, overdrafts and personal loans. Mortgages are long-term, lower-rate debts with different trade-offs.
What if a debt has a 0% promotional rate?
Enter 0% and note when the promotion ends. The avalanche will leave it until last, so check it will be cleared, or moved, before the rate jumps.
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General information, not personal financial advice. Results are estimates based on the inputs and assumptions shown.