Debt Avalanche Calculator
Estimate how long it could take to pay off multiple debts and how much interest you could save by using the debt avalanche method.
Overview
A debt avalanche calculator helps you estimate how quickly you could pay off your debts by focusing extra payments on the highest interest balance first. Enter your total debt, weighted average APR, minimum monthly payments, and any extra monthly payment to see your estimated payoff time and total interest.
How it works
The calculator estimates repayment using your combined debt balance, a weighted average annual interest rate, and a fixed total monthly payment. It converts the APR into a monthly rate and applies an amortization-style payoff formula to estimate how many months it would take to reduce the balance to zero. In a true debt avalanche plan, extra payments go to the highest interest debt first while minimums are maintained on the rest. Because this version uses combined totals rather than each debt separately, the result is a practical estimate rather than a debt-by-debt schedule.
How to use this calculator
- 1Enter the total balance of all debts you want to include.
- 2Add the weighted average APR across those debts.
- 3Enter the total of all minimum monthly payments.
- 4Add any extra amount you plan to pay each month.
- 5Review the estimated payoff time, total interest, and total amount repaid.
Example Calculation
Total debt balance
$15,000
Weighted average APR
18%
Number of debts
4
Total minimum monthly payments
$450
Extra monthly payment
$200
Estimated payoff time
29 months
If you owe $15,000 at a weighted average APR of 18% and pay $650 per month in total, you could repay the debt in about 30 months and pay roughly $4,500 in interest.
Frequently asked questions
What is the debt avalanche method?
The debt avalanche method focuses extra payments on the debt with the highest interest rate while you continue making minimum payments on all other debts.
What does this calculator estimate?
It estimates how long it may take to pay off your debts, how much interest you may pay, and your total repayment based on a fixed monthly payment.
Why does the calculator ask for a weighted average APR?
A weighted average APR gives a single blended rate across multiple debts, which helps create a simple overall payoff estimate when you are not entering each debt separately.
Is this the same as a full debt payoff schedule?
No. This calculator gives a simplified estimate. A detailed payoff schedule would require each debt balance, APR, and minimum payment separately.
Can extra monthly payments make a big difference?
Yes. Increasing your monthly payment usually shortens the payoff period and reduces the total interest paid.
What if my interest rates or minimum payments change?
If rates, fees, or required payments change over time, your actual payoff timeline and interest cost may differ from the estimate.
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Assumptions and warnings
Assumptions
- This calculator uses a weighted average APR rather than separate balances and rates for each debt.
- It assumes you keep making the same total monthly payment until all debts are repaid.
- It assumes extra payments are directed to the highest interest debt first, following the debt avalanche method.
- Results are estimates and do not include late fees, promotional rates, balance transfers, or changing minimum payments.
Warnings
- This calculator provides an estimate only and is not financial advice.
- If your monthly payment is too low relative to your interest rate, actual repayment may take longer or may not be possible without increasing payments.