Debt Avalanche Calculator
Pay debts highest interest rate first — the mathematically cheapest order, with the saving against the snowball shown.
The avalanche orders debts by interest rate, highest first, paying minimums on everything else and every spare dollar at the front.
How the debt avalanche calculator works
The avalanche orders debts by interest rate, highest first, paying minimums on everything else and every spare dollar at the front. Because interest accrues fastest on the highest rate, killing it first always minimises total interest.
It can feel slower, because the highest-rate debt is often not the smallest. The calculator reports when the first account clears so you can see what the discipline costs in patience.
Formula: order by interest rate descending; roll each cleared payment into the next
Worked examples
| Inputs | Time to clear everything | Note |
|---|---|---|
| Three debts, 300 extra | 2 years 10 months | highest rate first |
| Rates all equal | 2 years 10 months | the two methods converge |
| A bigger extra | 1 year 9 months | much faster |
FAQFrequently asked questions
What is the debt avalanche?
Paying the highest interest rate first, then rolling that payment into the next-highest.
Is it always cheaper?
Yes, mathematically — it minimises total interest. This page shows the saving against the snowball on your own numbers.
How much does it save?
It depends on the rate spread. With rates from 8% to 22% on typical consumer balances the difference is usually a few hundred; with a payday loan in the mix it can be thousands.
Which should I choose?
The avalanche if the saving is large or you are confident of finishing. The snowball if you need early wins to stay with it.
Does the order affect the payoff date?
Slightly. The avalanche is usually a month or two faster too, because less money goes to interest.
Where these figures come from
- CFA Institute — Quantitative Methods: The Time Value of Money — the discounting, annuity and IRR conventions used here
- US Federal Reserve — Regulation Z (Truth in Lending), APR calculation — why APR includes fees where a nominal rate does not
- Consumer Financial Protection Bureau — the US consumer finance regulator
Last checked: September 2026. These are the standard textbook formulas; the conventions named are those of the CFA Institute curriculum and ISO 80000 usage.