Debt Avalanche
Estimate payoff time avalanching debt by highest interest rate.
About Debt Avalanche
Extra money flows toward the highest APR balance, which removes the most expensive interest first before moving down the ladder. Paying the highest rate first usually saves the most total interest, making it ideal for disciplined savers on long timelines.
Formula
Debt Avalanche
Payoff months = -ln(1 - rate x debt / payment) / monthly rate
- weighted APR
- Blended average interest rate across all balances
Worked example
With the default values below, Debt Avalanche returns Payoff Time of 24. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Total debtminimum 0
- 15,000
- Weighted APRaccepts 0–100 %
- 9 %
- Monthly paymentminimum 1
- 700
Results
- Payoff Time
- 24 months
- Total Interest
- $1,800
- Strategy
- Target the highest-rate balance first to minimize interest
Step by step
- 1Values used
- 2Debt Avalanche
- 3Payoff Time= 24 months
- 4Total Interest= 1,800
- 5Strategy= Target the highest-rate balance first to minimize interest
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or fees or charges into account.
- Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Debt Avalanche calculated?
Payoff months = -ln(1 - rate x debt / payment) / monthly rate Extra money flows toward the highest APR balance, which removes the most expensive interest first before moving down the ladder.
Why does Debt Avalanche matter?
Paying the highest rate first usually saves the most total interest, making it ideal for disciplined savers on long timelines.
What values do I need to enter?
This calculator takes 3 inputs: Total debt, Weighted APR, Monthly payment. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.