Debt Payoff Calculator
Avalanche vs snowball, simulated month by month: your payoff order, months to debt-free, total interest under each method, and exactly what the avalanche saves you.
Last updated: October 2026
Your debts
Payoff order
| # | Avalanche (highest APR first) | Snowball (lowest balance first) |
|---|---|---|
| Enter your debts and click Compare. | ||
Avalanche vs snowball: what they are
Both methods work the same way: pay every minimum, then throw all extra money at one target debt. When that debt dies, its whole payment (minimum plus the extra) rolls into the next target, like a snowball gathering size. The only difference is the targeting order.
Avalanche targets the highest APR first. Every dollar of extra payment kills the most expensive debt, so it always costs the least in total interest. Snowball targets the smallest balance first. It costs a little more in interest, but you get your first "paid off" win sooner, which keeps many people motivated long enough to finish.
How the simulation works
The calculator simulates both strategies month by month: each month every debt accrues interest at its monthly rate (APR divided by 12), you pay each minimum, and the extra payment plus any freed-up minimums go to the current target. It repeats until every balance hits zero, counting months and total interest along the way. No closed-form formula can do this, because the payment allocation changes every time a debt is eliminated.
Worked example
Three debts and $300/month extra: Credit Card A ($8,500 at 24.99%, $180 minimum), Store Card ($2,300 at 19.99%, $65 minimum), Personal Loan ($12,000 at 9.50%, $260 minimum).
Avalanche attacks Credit Card A first (highest rate), then the Store Card, then the Personal Loan: debt-free in 40 months paying $4,989 in total interest. Snowball kills the Store Card first (smallest balance), then Credit Card A, then the Personal Loan: debt-free in 41 months paying $5,518 in interest. The avalanche saves $529 and one month here. With bigger rate gaps between debts, the savings grow into the thousands.
Which method should you choose?
If you are disciplined and motivated by numbers, take the avalanche: it is strictly cheaper. If you have quit payoff plans before, take the snowball: the early wins are worth a few hundred dollars in extra interest if they are what keeps you going. Either method beats the default, which is paying minimums for a decade. The real enemy is not the ordering, it is stopping.
Balance transfers and consolidation
A 0% balance transfer card or a consolidation loan can shortcut both methods by cutting the interest rate, but only if you run the numbers: transfer fees (often 3 to 5%) are real costs, the promotional rate expires, and the post-promo rate is often brutal. Model the transfer as a new debt in the calculator (balance plus fee, 0% APR for the promo months) to see whether it actually beats your current plan before you apply.
Debt Payoff FAQs
Which is mathematically better, avalanche or snowball?
The avalanche. Targeting the highest APR first always minimizes total interest for a fixed monthly budget. The snowball exists for psychology, not math: faster first payoffs keep people motivated.
Why do people choose the snowball if it costs more?
Because finishing debt is a behavior problem as much as a math problem. Clearing a whole debt in a few months feels like progress; grinding at a big high-rate balance for a year can feel hopeless. If the snowball is what keeps you paying, it is the right method for you.
Should I keep an emergency fund while paying off debt?
Yes, a small one first. Build about $1,000 in savings, then attack the debt. Without a buffer, every car repair or medical bill goes right back on a card and restarts the cycle you are trying to break.
Should I invest instead of making extra debt payments?
Compare the rates. Paying down a 24% card is a guaranteed 24% return, which no investment reliably beats. Once your remaining debt is under roughly 5 to 6%, investing the extra money instead becomes a genuine debate.
What if I can only afford the minimum payments?
Set the extra payment to zero and the calculator will show the grim truth: minimums on high-rate cards can take a decade or more. Even $25 extra a month meaningfully shortens the timeline, and it is worth finding in the budget.
Should I include my mortgage?
Usually not at first. Mortgage rates are far below credit card rates, so the avalanche would target the mortgage nearly last anyway. Clear high-rate consumer debt first, then decide whether extra mortgage payments beat investing.
How do 0% balance transfer cards fit in?
They help only if you pay the transferred balance off before the promotional period ends. Factor in the transfer fee (often 3 to 5%) and have a plan for the remainder, because the regular rate afterward is often 25% or more.
What happens if I miss a payment in real life?
The model assumes perfect payments. In reality a missed payment can trigger penalty APRs near 30%, late fees, and credit damage that raise your future borrowing costs. Automate at least the minimums so the plan survives a busy month.
Should I close credit cards after paying them off?
Usually keep them open at zero balance. Closing cards reduces your available credit and can shorten your credit history, both of which may lower your score. The key change is behavioral: stop carrying a balance, not stop having the card.
Does the extra payment really make that much difference?
Yes, disproportionately. Extra payments attack principal directly on your most expensive debt, which cuts the interest charged every following month. That compounding works in your favor, which is why $300 extra can save thousands in interest.