Debt Payoff Calculator
Enter your debts and one extra payment, and see both payoff strategies run against each other: how long each takes, what each costs in interest, and which one actually wins for your numbers. Everything runs in your browser.
Snowball vs. avalanche
Both methods do the same thing: pay the minimum on everything, then throw every spare dollar at one debt until it dies, and roll that freed-up payment into the next one. They disagree on only one question — which debt goes first.
Snowball — smallest balance first
Ignore the interest rates. Attack the smallest balance, clear it, feel the win, move on. Debts disappear from your list quickly, which is the entire point: it is a motivation strategy wearing a maths costume.
Avalanche — highest rate first
Ignore the balances. Attack the most expensive interest rate, whatever it is attached to. You kill the fastest-growing debt first, so less interest accrues overall. It is always the cheaper route — but your first win can take a while if the priciest debt is also the biggest.
The honest trade-off
Avalanche wins on paper, every time. The question is whether you will still be doing it in month 18. A snowball plan you finish beats an avalanche plan you abandon in month five — and that is not a maths problem, it is a human one.
Why the order matters
The default numbers above, and why they split the two methods apart.
| Debt | Balance | APR | Minimum | Snowball order | Avalanche order |
|---|---|---|---|---|---|
| Small card | $1,500 | 12% | $40 | 1st | 3rd |
| Big card | $7,000 | 27% | $175 | 3rd | 1st |
| Store card | $3,000 | 22% | $80 | 2nd | 2nd |
The two methods completely disagree on the first and last debt. Snowball clears the $1,500 card in a few months — a fast, satisfying win — but leaves the $7,000 at 27% compounding the whole time. Avalanche goes straight for that 27% and starves it.
Result on these numbers: snowball takes 33 months and $4,554.73 in interest, avalanche takes 31 months and $3,840.26. Avalanche saves $714.
Notice the catch, though: if the small cheap debt had also been the smallest and the priciest, both methods would pick the same order and the difference would vanish entirely. The gap only appears when balance and rate disagree.
Or change the rates entirely
Both methods accept your interest rates as fixed and only argue about order. There is a third move: replace the rates.
If you qualify for a debt consolidation loan below your current average rate, you cut the interest itself rather than just re-sequencing it — and then there is only one balance left to attack. Run your numbers through the debt consolidation calculator to see whether that beats either method here.
It is not always the answer. If your credit will not get you a better rate, avalanche on your existing debts is the cheapest path available — and it costs nothing to start today.
Debt payoff calculator FAQ
What is the debt snowball method?
Pay the minimum on every debt, then throw every spare dollar at the smallest balance, ignoring rates. When it clears, its payment rolls into the next-smallest, so the amount attacking each debt snowballs. It is built for motivation — you get a win quickly.
What is the debt avalanche method?
Same idea, different target: spare dollars go to the highest interest rate regardless of balance. Because you kill the most expensive interest first, it is mathematically the cheapest way out.
Which is better, snowball or avalanche?
Avalanche always costs less — on the defaults here it saves about $714 and finishes 2 months sooner. But snowball clears an individual debt faster, and people who need visible wins often stick with it. The best method is the one you will actually finish.
How does this calculator work?
It simulates every month twice. Each month it charges interest on each balance, pays every minimum, then sends whatever is left in your budget to one target — smallest balance (snowball) or highest rate (avalanche). When a debt clears, its payment frees up for the next target. Repeat until everything is zero.
What if my minimums do not cover the interest?
Then balances grow instead of shrinking and neither method finishes. The calculator says so directly. It means you need a different plan — consolidating into one lower-rate loan, or talking to a nonprofit credit counselor.
Should I consolidate instead?
They solve different problems. Snowball and avalanche change the order but not the rates. Consolidation replaces the debts with one loan at a lower rate, cutting the interest itself. If you qualify below your current average, consolidating and then attacking one balance is usually cheapest.
Does the extra payment amount matter much?
Enormously — more than the method. Extra money goes straight to principal, removing interest for every remaining month. Raising the extra payment usually beats switching strategies, so your budget is the real lever.
Or stop fighting the rate and replace it.
If you qualify below your current average rate, one consolidation loan beats any ordering trick. Check in about 5 minutes — soft check, no impact to your credit.
Related tools & guides
- Debt consolidation calculator — what one lower-rate loan would save you.
- How to consolidate credit card debt — loans, transfers and DMPs compared.
- Is debt consolidation a good idea? — when it works and when it backfires.
- Amortization calculator — the full month-by-month schedule for any loan.