Debt Snowball vs Avalanche Calculator
On three example debts — $12,000 at 14%, $5,000 at 10%, $3,500 at 6%, with a $300 monthly extra — the avalanche method finishes in 35 months with $3,429 of interest, while snowball takes 36 months with $4,234. Avalanche saves $806 here because the highest rate sits on the largest balance.
Snowball wins on momentum, avalanche wins on maths — and most people do best with the one they actually stick to.
The balance of power is the balance itself. Both methods use the same $715 monthly budget. Avalanche aims the $300 extra at the 14% loan first and saves $806; snowball aims it at the $3,500 loan first and finishes one month later.
Calculator
Enter up to three debts and your extra monthly payment. Results update instantly.
How This Calculator Works
Both methods pay every minimum every month, then throw the entire extra — plus the freed minimum of each cleared debt — at one target. Snowball targets the smallest balance, avalanche the highest rate. The budget never changes; only the aim does.
Avalanche always pays the least interest in theory, because expensive balance is removed first. Snowball clears a whole debt sooner, which is why behavioural studies find people finish it more often. The calculator shows both so you can see what the motivation costs.
interestm = balance × rate/12 — target gets minimum + extra + freed minimums; others get minimums
Worked example
Using the defaults — $12,000 at 14% (min $250), $5,000 at 10% (min $75), $3,500 at 6% (min $90), plus $300 extra:
Snowball order (smallest balance): $3,500 → $5,000 → $12,000. Avalanche order (highest rate): $12,000 → $5,000 → $3,500.
Month by month, each balance accrues its own interest, minimums go out, and the $715 attack payment ($300 extra plus freed minimums as debts clear) hits the current target until it reaches zero.
Avalanche finishes in 35 months with $3,429 of interest; snowball in 36 months with $4,234. The gap is $806 — the price of killing the small loan first when the big one costs 14%.
The calculator above returns these figures exactly. If your highest rate sits on your smallest balance, both methods agree and the gap collapses to nearly zero.
The same three debts, two payoff orders
Identical budget, identical debts — only the targeting order differs.
| Method | First target | Months | Total interest |
|---|---|---|---|
| Snowball (smallest first) | $3,500 auto loan | 36 | $4,234 |
| Avalanche (rate first) | $12,000 personal loan | 35 | $3,429 |
| Minimums only, no extra | — | 69 | $7,933 |
Minimums-only stretches to 69 months with $7,933 of interest — the $300 extra wipes out nearly half the interest and more than three years of payments under either method.
Common mistakes with this calculation
- Chasing the method instead of the budget. The $806 gap is real but small next to the $3,699 the $300 extra saves under either method. Protect the extra payment first; argue about targeting second.
- Paying extra without killing the target. Extra spread thinly across all debts saves far less than extra concentrated on one target. One debt at a time is the whole technique.
- Ignoring rate resets. A 0% intro card that resets to 24% changes the avalanche order mid-plan. Re-run the calculator whenever a rate changes.
- Closing the oldest card in celebration. Closing your oldest account shortens your credit history and can dent the score you just rescued. Keep it open with a tiny recurring charge.
When this calculator does not apply
- The calculator models fixed rates and fixed minimums. Variable rates, penalty APRs, and minimums that reset with the balance are approximated, not tracked.
- It assumes the full extra is available every month. Irregular income needs a manual month-by-month plan instead.
- Balance transfers with fees are excluded — add the fee to the receiving balance yourself.
- It does not model taxes, hardship programmes, or settlement negotiations.
Frequently Asked Questions
Which is better, snowball or avalanche?
Avalanche always costs less interest on paper — $806 less here. Snowball clears a debt sooner, which helps people stay the course. Pick avalanche if you trust your discipline; pick snowball if you need early wins.
How much does $300 extra a month save?
On these three debts, $3,699 of interest versus minimums only, and 33 months of payments — nearly three years. The extra is the strategy; the method is the fine-tuning.
Should I save while paying off debt?
Keep a small starter emergency fund ($1,000 is the usual line) so a surprise does not become new debt, then throw everything at the target. High-rate debt above 8-10% almost always beats investing the same dollar.
Does the order matter if rates are equal?
No — with equal rates both methods produce identical interest, so snowball wins by default on motivation alone.
Sources & Methodology
This calculator uses standard financial formulas. See our methodology page for the full derivation.
- How to Pay Off Debt Consumer Financial Protection Bureau
- Tackling Credit Card Debt Experian
Last reviewed .
Key takeaways
- Same $715 budget: avalanche takes 35 months and $3,429 of interest; snowball 36 months and $4,234.
- The $806 gap comes from the 14% rate sitting on the largest balance.
- Either method with $300 extra beats minimums-only by about $3,700 and nearly three years.
- Freed minimums roll into the attack — the payment stays constant until every debt is gone.
- Pick the method you will follow for three years, not the one that wins a spreadsheet.