Debt Payoff Calculator
Snowball vs avalanche: compare both payoff strategies across all your debts at once.
Two payoff strategies dominate personal-finance advice. The avalanche attacks the highest APR first — mathematically cheapest, because the most expensive debt dies first. The snowball clears the smallest balance first, banking quick wins that keep motivation alive.
Your total monthly budget is every minimum payment plus this extra amount. As each debt dies, its minimum rolls into the attack payment automatically.
How to use
- Add a row for each debt: its balance, APR and minimum monthly payment (all on your statements).
- Enter any extra amount you can pay each month on top of the minimums.
- Click "Compare strategies" to see both debt-free dates and total interest side by side.
- Whichever you pick, the mechanics are the same: minimums on everything, every spare dollar aimed at one target debt.
About this tool
This calculator simulates both, month by month, across all your debts at once: interest accrues, minimums are paid on everything, and your extra payment plus the minimums of already-cleared debts roll into the current target. The difference between the two strategies is often hundreds or thousands of dollars — and occasionally zero, which is itself worth knowing.
The model assumes fixed APRs, no new charges and no fees. Everything runs in your browser; your debts are never sent anywhere.
How it works
Each month the simulator charges interest (balance × APR ÷ 12) on every debt, pays each minimum, then aims the rest of your fixed monthly budget at one target: the highest APR (avalanche) or the smallest balance (snowball). When a debt dies, its minimum joins the attack payment — the "roll-down" that makes both strategies accelerate.
Total interest is the sum of every month's interest charges across all debts until the last balance reaches zero. Debt-free date is the month that happens.
Worked examples
Two small debts, $100/month budget: Debt A: $500 at 12% APR, $25 minimum. Debt B: $300 at 24% APR, $25 minimum. Extra $50. The avalanche (B first) clears both in 9 months with $46.62 interest; the snowball picks the same order here — B is also the smallest balance — so the two strategies tie.
Frequently asked questions
Which strategy is actually better?
On pure math, the avalanche — it minimizes interest in almost every case. But research on real households finds people who clear small balances early are more likely to finish the plan at all. If the interest difference is small, take the motivation.
What does "minimum payment" mean here?
The fixed minimum you enter for each debt. Real card minimums shrink as the balance falls (often interest plus 1% of the balance); enter a typical recent minimum, and treat the result as a solid estimate.
Why would the snowball ever cost the same?
When the smallest balance is also the highest APR, both strategies attack debts in the same order. They can also tie when one debt dwarfs the others.
My plan says "never clears" — what now?
Some payment is not covering its debt's monthly interest. Raising the extra payment even slightly usually flips the plan back to a finish line, because the freed minimums start compounding in your favor.
Is my data sent anywhere?
No. Every calculation runs in your browser. Nothing you type ever leaves your device.
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