🧮 Debt Snowball / Avalanche Calculator — list each debt, pick a strategy, and see your debt-free date in seconds.
Methodology
The calculator runs a month-by-month amortisation across all debts. For each month it: (1) accrues interest on each balance at APR ÷ 12, (2) applies the minimum payment to every debt, then (3) directs your extra monthly payment plus any freed-up minimums (the "snowball") at the focus debt. The focus debt is the smallest remaining balance under snowball, or the highest APR under avalanche. When a debt is cleared, its minimum is rolled into next month's snowball — which is why the last few debts disappear so quickly.
The snowball strategy is most associated with Dave Ramsey's The Total Money Makeover (2003), which popularised the smallest-balance-first approach for its behavioural momentum. Avalanche is the mathematically optimal interest-minimising order. This is a pure-math calculator with no external data sources — the only inputs are the ones you enter above.
Last verified: May 2026.
Frequently Asked Questions
What is the debt snowball method?
The snowball method, popularised by Dave Ramsey, is to pay minimums on every debt and direct any extra cash at the smallest balance first. When that debt is gone, you "snowball" its minimum payment into the next-smallest debt, and so on. The wins-first psychology beats the slightly worse maths for most people.
Snowball vs avalanche — which is better?
Avalanche (highest APR first) saves more interest mathematically. Snowball (smallest balance first) gives quicker emotional wins. The interest difference is usually small — a few hundred dollars — and the snowball wins more often in real life because people stick with it. Use this calculator to see your specific gap.
Should I include my mortgage in the snowball?
Usually no. Mortgages are low-rate, long-term, and tax-treated. Standard advice is to snowball consumer debt (credit cards, personal loans, car loans, store cards) and treat the mortgage as a separate, low-priority payoff goal.
What if my minimum payments don't cover the interest?
You're going backward — interest is being added faster than payments reduce the balance. The calculator returns an error in this case. Increase the extra monthly payment or call the lender to negotiate a hardship plan.
How does extra money "snowball"?
When debt #1 clears, its minimum payment is freed up and added to your extra payment for debt #2. When debt #2 clears, both freed minimums plus extra hit debt #3. Each clear-out grows the snowball — the last debt is paid off astonishingly fast.