Snowball vs. avalanche: two ways to the same finish line
Most debt calculators model one payoff method and leave you guessing about the other. This one runs both against the exact same monthly budget so you can see the real trade-off: avalanche almost always costs less, but snowball can be easier to stick with. The right answer is the plan you’ll actually finish.
The core idea
Pay the minimum on every debt, then throw all spare cash at onetarget. When it clears, its payment rolls onto the next target. The only choice is the order:
- Avalanche — highest APR first. Minimises total interest. Mathematically optimal.
- Snowball — smallest balance first. Maximises quick, motivating wins.
What makes this calculator different
- Both strategies, side by side. Two result cards and a two-line chart make the trade-off concrete instead of theoretical.
- A clear verdict. We tell you exactly how much interest and time the avalanche saves — or note when snowball’s motivation edge is worth the small cost.
- The rollover modelled correctly. Your budget stays constant as debts clear, so every freed-up minimum accelerates the next payoff.
- Honest warnings. If a minimum payment can’t outrun its interest, we flag the debt that will never clear.
Frequently asked questions
What’s the difference between the snowball and avalanche methods?+
Both put every spare dollar toward one debt at a time while paying the minimums on the rest. The difference is which debt you attack first. The debt snowball targets the smallest balance first, regardless of interest rate, so you knock out whole debts quickly. The debt avalanche targets the highest interest rate (APR) first, regardless of balance, so you stop the most expensive interest as soon as possible. As each debt clears, its payment "rolls over" onto the next target — which is what accelerates the payoff toward the end.
Why is the avalanche method mathematically optimal?+
Interest is charged as a percentage of each balance, so the highest-APR debt grows fastest. By directing extra money there first, the avalanche method eliminates the most expensive interest the soonest, which always results in the least total interest paid and — for the same monthly budget — the fastest overall payoff. No ordering can beat it on pure dollars and cents.
If avalanche is cheaper, why would anyone choose snowball?+
Because paying off debt is as much behavioral as mathematical. The snowball method clears entire debts quickly, and each balance that disappears is a visible win that builds momentum and motivation. Research and many financial coaches find that people are more likely to actually stick with a payoff plan when they see fast progress. If the interest difference between the two is small, the strategy you’ll follow through on beats the one that’s optimal only on paper.
What is the “rollover” budget and why does it matter?+
This calculator holds your total monthly payment constant: the sum of every debt’s minimum payment plus your extra amount. When a debt is paid off, its minimum doesn’t disappear from your budget — it rolls onto the next target debt. That compounding redirection is the engine behind both methods, and it’s why keeping the same monthly amount even as debts clear is so powerful.
Can a debt never get paid off?+
Yes. If a debt’s minimum payment is smaller than the interest it accrues each month, the balance grows faster than you pay it and it will never clear on its own. This calculator flags that situation. The fix is to direct more money at it — which is exactly what the avalanche method does, since a debt that’s outrunning its payment is almost always a high-APR one.
Disclaimer: This calculator is for educational purposes only. It assumes fixed balances, rates, and minimums and that interest compounds monthly. Real cards and loans vary in how interest is computed, and minimums often change as balances fall. It is not financial advice.