Debt Snowball Calculator
List your debts smallest-first, throw every spare dollar at the littlest balance, and watch payments roll forward like a snowball. This planner shows your payoff order, debt-free date, and how the method compares to pure math.
Your results
Charts & visualization
Total debt over time
Both methods reach zero; they differ in which debt disappears first and how much interest accrues along the way.
Your snowball payoff order
Every chart’s underlying numbers are available as text — use the “view as table” control under each chart.
How it works
Each month the simulator:
- Accrues interest on every open balance.
- Pays every debt’s minimum payment.
- Dumps your entire extra amount onto the target debt — the smallest balance for snowball, highest APR for avalanche.
When a debt dies, its minimum payment joins the budget next month, growing the snowball automatically. That roll-forward effect is why the final debts fall fast.
Snowball vs avalanche: avalanche always costs less or equal interest because it kills the most expensive money first. Snowball front-loads psychological wins by clearing accounts quickly — research on motivation suggests people who see early wins are more likely to finish. The honest answer: pick the one you will actually complete.
Formula used
Target (snowball)— smallest remaining balanceTarget (avalanche)— highest remaining APRRoll-forward— paid-off debts’ minimums stay in the budget
Example calculation
With the three default debts ($27,000 total) plus $100 extra per month, the snowball clears the store card first — freeing its $120 minimum for month two onward — and reaches debt-free in about 5 yrs 6 mo with $7,749 of interest. Pure avalanche would save about $2,893 more but leaves the store card alive for years. Seeing accounts disappear has kept more snowballs rolling than basis points ever have.
Assumptions & limitations
- Minimum payments stay constant; real card minimums decline as balances fall (which slows payoff slightly).
- No new borrowing while the plan runs.
- All payments land on time; no fees or penalty rates modeled.
- Balances and APRs entered reflect your actual statements for best results.
Results are planning estimates based on your inputs and the stated assumptions — not financial advice or a loan offer. Verify important figures with your lender or advisor.
Frequently asked questions
Which is better: snowball or avalanche?
Mathematically, avalanche — it minimizes interest. Behaviorally, snowball’s early wins help many people stick with the plan. The best method is the one you finish; the interest gap is often smaller than expected.
How much extra should I add to my snowball?
Whatever survives after essentials and a starter emergency fund. Even $50/month measurably shortens the timeline — test a few amounts above and watch the debt-free date move.
Should I include my mortgage in the snowball?
Most plans exclude mortgages because of their size and low rates relative to consumer debt. Include auto loans, cards, student loans, and personal loans first.
What happens if a debt has 0% interest?
Its position barely matters for interest math. Snowball may still prioritize it for a quick win, which is fine — the simulator handles it naturally.