Debt Avalanche Calculator
Enter your debts and the avalanche method targets the highest interest rate first — the order that costs the least. See your debt-free date, what each debt costs you in interest, and exactly what choosing the snowball instead would add.
Your Debts
2/6 debtsWhy Rate Order Is the Cheapest Order
Interest is a price, and you can choose which one to stop paying. A dollar of balance at 24% costs you 24 cents a year; the same dollar at 5% costs five. Since your extra payment can only go to one debt at a time, sending it to the highest rate buys the largest reduction in future interest per dollar spent. Repeat that every month and no other ordering can beat it — this is not a strategy so much as an arithmetic result.
Balance size is a distraction. The size of a debt determines how long it takes to clear, not how expensive it is per dollar. A small balance at 5% is cheap to carry and feels satisfying to kill; a large balance at 24% is quietly costing you more every month you leave it alone. The avalanche ignores how a debt feels and ranks purely on what it charges.
Freed minimums are what accelerate the plan. When a debt clears, its minimum payment does not go back into your budget — it joins the extra payment attacking the next debt. The pot grows each time an account closes, which is why the last debts fall much faster than the first. Both methods use this roll; they only disagree about the order the debts should fall in.
The honest caveat: the avalanche is optimal only if you follow it. The method is measurably cheaper on paper and measurably harder to stick with, because the reward comes last. If you have abandoned a payoff plan before, the cheaper method on paper may not be the cheaper method for you.
A Worked Example
Three debts totalling $25,000, with $560 in combined minimum payments and $300 extra available each month:
| Debt | Balance | Rate | Minimum |
|---|---|---|---|
| Medical bill | $2,000 | 5% | $50 |
| Credit card | $9,000 | 24% | $180 |
| Car loan | $14,000 | 7% | $330 |
These three disagree, which is what makes them worth modelling: the smallest balance carries the lowest rate, so the two methods pick opposite starting targets.
| Method | Order Cleared | Debt Free | Interest |
|---|---|---|---|
| Avalanche | Card (mo 24) → Car (mo 34) → Medical (mo 35) | 35 mo | $4,360 |
| Snowball | Medical (mo 6) → Card (mo 27) → Car (mo 36) | 36 mo | $5,066 |
The avalanche saves $706 and finishes one month sooner. That is the whole advantage — real, but smaller than the rhetoric around these methods suggests. What the table shows more starkly is the other column: the snowball closes an account in month 6, while the avalanche closes nothing until month 24. Eighteen months of identical effort with nothing visibly finished is the real price of the cheaper plan.
The size of the extra payment matters more than the method. Drop from $300 extra to nothing and this same set of debts takes 68 months instead of 35, with the avalanche's advantage shrinking to $108. Raise it to $200 and the avalanche saves $831. In every case, the amount you send beats the order you send it in — settle the budget first, then argue about ordering.
Choosing Between the Two
Run both and look at the gap, not the winner. The calculator above switches between methods on the same debts. If the avalanche saves a few hundred dollars, that is a preference question and either answer is defensible. If it saves several thousand — which happens when a large balance sits at a card rate — the discipline is worth buying.
Your history with plans is real evidence. This is not a character judgement; it is a data point about which plan gets finished. A method you abandon in month eight costs infinitely more than the one you complete. If previous attempts stalled, the snowball's early wins are worth paying a few hundred dollars for.
A hybrid is allowed. Clear one small balance for momentum, then switch to strict rate order for everything remaining. You give up a fraction of the avalanche's saving and remove most of what makes it hard to sustain. Nobody is checking which method you used.
Assumes fixed rates, no new borrowing, and minimum payments that stay level rather than shrinking with the balance. Credit cards recalculate their minimum each month, which stretches the payoff further — model a single card precisely with the credit card payoff calculator.
Frequently Asked Questions
How much does the debt avalanche actually save?
Less than the internet implies, but reliably more than zero. Take $25,000 across three debts — a $2,000 medical bill at 5%, a $9,000 credit card at 24%, and a $14,000 car loan at 7% — with $560 in minimums and $300 extra a month. The avalanche clears everything in 35 months for $4,360 in interest; the snowball takes 36 months and $5,066. The avalanche saves $706. The gap widens when the rate spread is wide and narrows to almost nothing when your debts sit close together.
Why does the avalanche feel slower even though it is faster?
Because the first win takes far longer to arrive. In the example above, the snowball clears the medical bill in month 6. The avalanche attacks the 24% credit card first and does not fully retire anything until month 24 — eighteen months of paying without a single account closing. Both plans finish within a month of each other, but only one of them gives you evidence it is working early on. That is the entire tradeoff, and it is a question about you rather than about arithmetic.
Does the avalanche method still matter if my rates are similar?
Barely. The avalanche wins by moving money from a low rate to a high one, so its advantage is proportional to the spread between your rates. If everything you owe sits between 6% and 8%, the two methods finish within a few dollars of each other and you should simply pick whichever you will actually follow. Run both modes in the calculator above: if the interest difference is under a few hundred dollars, that is your answer.
What if my highest-rate debt is also my largest?
Then the avalanche demands the most patience it ever will, and the case for it is strongest. A large balance at a high rate accrues more interest per month than anything else you owe, so every month you delay is expensive. The compromise many people use is to clear one genuinely small balance first for the momentum, then switch to strict rate order for everything after — it costs a little and it removes the hardest part of the plan.
Can I switch from the snowball to the avalanche partway through?
Yes, and there is no penalty for doing it. Neither method is a product you sign up for; both are just rules for where the extra payment goes each month. Switching mid-plan simply redirects the next payment to a different debt. If you started with the snowball for early momentum and now want the cheaper path, change the target the next time you pay and leave the minimums on everything else untouched.
Should I include my mortgage in the avalanche?
Usually no. A mortgage at 6% or 7% is almost always the lowest rate you carry, so a strict avalanche puts it last anyway — including it changes nothing about the order. It also distorts the payoff date, because a 30-year balance dwarfs consumer debt and makes the plan look hopeless. Run the avalanche on your consumer debts, and treat the mortgage as a separate decision once they are gone.
Related Calculators
- Debt Snowball Calculator
The same engine ordered by balance instead — smallest debt first.
- Credit Card Payoff Calculator
One card at a time, with the shrinking minimum payment modelled properly.
- Student Loan Payoff Calculator
Extra payments against a student balance, where forgiveness changes the maths.
- Compound Interest Calculator
What the same monthly payment earns once every debt is behind you.
For the reasoning behind the choice rather than the arithmetic, read debt avalanche vs snowball and debt payoff strategies.