Snowball — smallest balance first
Avalanche — highest rate first
The difference
Snowball clears your smallest balance first — quick early wins that help with momentum. Avalanche targets your highest interest rate first, which mathematically saves the most money. Both apply your extra payment on top of every debt's minimum. Figures are estimates and don't include fees or promotional rates.
What is a debt snowball calculator?
A debt snowball calculator compares the two standard ways of clearing multiple debts at once, so you can see what choosing between them actually costs.
Both methods work the same way at the top: you pay every debt's minimum, then put every spare dollar toward one target debt. The snowball targets your smallest balance first, clearing whole debts quickly. The avalanche targets your highest interest rate first, which is always mathematically cheaper.
This tool runs both simulations against your real debts and shows the difference in months and dollars — which is usually smaller than people expect, and occasionally much larger.
Two strategies, one real difference
Both methods pay every minimum, then throw all spare money at one target debt. They differ only in which debt gets targeted first — and that single choice changes both your total interest and how the process feels.
Snowball
Attack the smallest balance first, regardless of rate. You clear whole debts quickly, which builds visible momentum and frees up minimum payments sooner.
Avalanche
Attack the highest interest rate first. This is always the mathematically cheapest route — you're killing your most expensive debt while it's largest.
Then roll it over
When a debt clears, its minimum payment joins your extra payment and rolls onto the next target. That growing payment is the "snowball" the method is named for.
Which one should you actually pick?
The honest answer is that the gap between them is often smaller than people expect — and the best method is the one you'll finish.
Three debts, $200/month extra:
- $1,000 at 5% (min $30)
- $5,000 at 24% (min $120)
- $12,000 at 12% (min $250)
Avalanche wins by $308 and one month. Real, but not enormous — and snowball clears that first debt in 5 months, versus month 36 under avalanche — a genuine psychological difference.
Rule of thumb: if your rates are spread widely (say a 6% loan alongside a 27% card), avalanche's advantage is large enough to matter. If your rates are all clustered close together, take snowball and enjoy the momentum — you're barely paying for it.
When snowball is genuinely the better call
If you've previously started a payoff plan and abandoned it, the behavioural evidence favours quick wins. A method you finish beats an optimal method you quit at month seven. Research on debt repayment has repeatedly found that people who close accounts early are more likely to see the process through.
When avalanche is clearly worth it
If you carry a high-rate card alongside low-rate installment debt, the difference compounds fast. A $10,000 balance at 24% accrues about $200/month in interest — every month you spend targeting a 5% student loan instead is money burned.
Common questions
The things people usually want to know before trusting a number like this.
How do I work out what to pay to be debt-free by a certain date?
Switch the toggle above to “Clear it by a deadline” and set your target number of months. The calculator then works backwards and tells you the extra monthly payment required on top of your minimums, for each strategy. Because the avalanche method wastes less on interest, it usually needs slightly less extra money to hit the same date.
Do I keep paying minimums on everything?
Yes, always. Both strategies assume every debt receives its minimum every month — missing one triggers late fees, penalty APRs, and credit damage that dwarf any interest you'd save. Only your surplus goes to the target debt.
What happens when a debt is paid off?
Its minimum payment gets added to your extra payment and rolls onto the next debt in line. This is the core mechanic of both methods and why payoff accelerates dramatically toward the end. This calculator models that rollover automatically.
Should I consolidate instead?
A consolidation loan or balance transfer can genuinely help if the new rate is meaningfully lower and you don't run the old cards back up. Two cautions: transfer fees (typically 3–5%) eat into the benefit, and 0% promotional periods end — model what the rate becomes after the promo when deciding.
Does this account for new spending on my cards?
No. It assumes balances only go down. If you're still adding to a card each month, your real payoff will be slower than shown. Pausing new charges on the debt you're attacking is usually the single highest-impact change you can make.
What about my credit score during payoff?
Paying down revolving balances lowers your credit utilization, which typically helps your score. Installment loans matter less. Keep paid-off cards open rather than closing them — closing reduces your available credit and can nudge utilization back up.
Guides on paying off debt
Plain-English explanations of the concepts behind this calculator.
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