A debt snowball vs. avalanche calculator compares the two most popular debt-payoff strategies on your own debts: the snowball attacks the smallest balance first for quick wins, and the avalanche attacks the highest interest rate first to minimize total interest. Enter up to three debts’ balances and rates, add the extra amount you can pay each month, and the tool simulates both strategies side by side, showing the months to debt-free and the total interest for each.
This free online tool is for anyone juggling several balances — credit cards, personal loans, medical bills — and unsure which to pay off first. You list every debt once, add the extra amount you can pay each month above the minimums, and the calculator runs both strategies month by month: minimums on everything, with all extra money aimed at one target debt. When a target is cleared, its minimum rolls into the next target, accelerating the payoff like a snowball. The result tells you which strategy gets you debt-free sooner, how much interest each costs, and exactly which debt to attack first. It runs instantly in your browser with no sign-up and no data stored.
Worked example
Inputs — three debts with $160 in estimated minimums, plus $200 extra per month ($360 total):
| Debt | Balance | APR | Minimum |
|---|---|---|---|
| Store card | $4,000 | 24% | $80 |
| Credit card | $2,500 | 19% | $50 |
| Personal loan | $1,500 | 12% | $30 |
(Minimums are the tool’s standard estimate — the greater of $25 or 2% of each balance.)
Snowball order: $1,500 → $2,500 → $4,000. Debt-free in 29 months, total interest $2,390.97 — and the $1,500 loan clears first, a fast early win.
Avalanche order: $4,000 (24%) → $2,500 (19%) → $1,500 (12%). Debt-free in 28 months, total interest $1,905.11.
The avalanche finishes 1 month sooner and saves $485.86 in interest here — because the 24% store card is also the largest debt, targeting the highest rate first does double duty. When the highest-rate debt is small, the two strategies often land within a few dollars of each other.
How to use it
- Enter each debt's Balance and APR — up to three debts. (Minimum payments are estimated automatically at the greater of $25 or 2% of each balance.)
- Enter the Extra monthly payment — the total amount you can pay above all minimums combined.
- The tool runs both strategies automatically — snowball (smallest balance first) vs. avalanche (highest rate first).
- Read your result: the recommended payoff order, the months to debt-free, and the total interest under each strategy.
The formula behind it
Frequently asked questions
Which is better: debt snowball or debt avalanche?
The avalanche costs less interest, always — paying the highest rate first is mathematically optimal. The snowball clears a debt fastest, which helps people who need momentum to stay on plan. Run both on your real numbers: if the interest gap is small, pick the strategy you will actually stick with, because an abandoned plan costs more than either.
How much can the avalanche save versus the snowball?
It depends on how your rates and balances line up. In the example above — three debts totaling $8,000 — the avalanche saved $486 in interest and finished 1 month sooner versus the snowball. The gap widens when a large balance carries a much higher rate than the rest, and shrinks when rates are close together or the smallest balance also has the highest rate.
What if two of my debts have the same interest rate?
Then the strategies agree on ordering: for equal rates, always target the smaller balance first, since either way the interest cost is identical and the smaller debt clears sooner. The calculator applies this tie-break automatically when it builds the payoff order.
Does this calculator include late fees or penalties?
No. It models balances, interest rates, minimums, and your extra payment only. Fees, penalty APRs, and rate changes are not part of the simulation. To approximate a fee, add it to that debt's balance before running the calculator — and keep accounts current so the real payoff tracks the plan shown.
Can I add a new debt after I start my payoff plan?
Yes — re-run the calculator with the new debt added and your updated balances. New debt changes the payoff order under both strategies and pushes the debt-free date out. The honest math usually shows that new borrowing costs more than the minimum payments suggest, which is itself useful information.