What is the debt avalanche method?

The debt avalanche strategy directs any extra money toward the debt with the highest interest rate first while making minimum payments on all others. Once the highest-rate debt is paid off, you "avalanche" that freed payment to the next highest. Mathematically, the avalanche method minimizes total interest paid and payoff time.

What is the debt snowball method?

The debt snowball strategy targets the debt with the smallest balance first regardless of interest rate. Paying off small debts quickly creates psychological wins and momentum. The snowball method typically costs more in interest than the avalanche but can be more motivating for some people.

Which method should I choose?

If your goal is to minimize interest paid, choose the avalanche. If you need quick wins for motivation to stay on track, choose the snowball. The best strategy is the one you will actually follow. Use the "Compare" mode to see the exact dollar and time difference for your specific debts.

What is the "extra monthly payment"?

This is any amount above your combined minimum payments that you can put toward debt each month. Even an extra $50–$100/month can dramatically reduce your payoff time and total interest. The calculator applies this extra money to your target debt (highest APR or lowest balance, depending on strategy).

Why does the calculator warn "minimum payment never pays off this debt"?

This happens when your minimum payment is less than the monthly interest charge. Each month your balance grows instead of shrinking. You must increase the minimum payment above the monthly interest to make progress. Monthly interest = Balance × (APR ÷ 12 ÷ 100).

Debt Payoff Calculator - Avalanche & Snowball

Avalanche vs. snowball: which is better?

The debt avalanche method orders debts by interest rate, highest APR first. You make minimum payments on everything and throw every extra dollar at the highest-rate debt. When it's gone, that minimum payment rolls into the next. Mathematically, this minimizes interest paid and total payoff time.

The debt snowball method targets the smallest balance first. Paying off a debt completely (even a small one) creates a motivational win. For many people, the psychological boost helps them stay on track even if they pay slightly more interest overall.

The power of extra payments

Adding even a small extra amount to your monthly payment has a compounding effect: paying off one debt frees that minimum for the next, cascading through your debt list. A $100/month extra payment on a $10,000, 18% APR credit card cuts the payoff time from over 30 years to under 4, saving thousands in interest.

Why minimum payments barely help

Minimum payments on high-APR credit cards are often set to 1–2% of the balance or a fixed $25, whichever is larger. At 20% APR, roughly 1.67% of the balance accrues each month as interest. A $5,000 balance at 20% costs ~$83/month in interest alone. A $100 minimum payment applies only $17 to principal, meaning it takes decades to pay off.

How the calculator works

Each month the calculator:

Accrues interest: interest = balance × (APR / 12 / 100)
Applies each debt's minimum payment.
Funnels any extra payment (plus freed minimums from paid-off debts) to the target debt.
Repeats until all balances are zero or 600 months is reached.

Results are in nominal dollars. The calculator runs entirely in your browser. No data is sent anywhere.

Debt-to-income ratio (DTI)

DTI is the percentage of your gross monthly income that goes toward debt payments (mortgage, auto, credit cards, student loans). Formula:

DTI = (Total Monthly Debt Payments / Gross Monthly Income) × 100%

<36%: Healthy DTI. Lenders view you as low risk.
36–43%: Acceptable for most mortgages (qualified mortgage limit is 43%).
>43%: Risky. Difficult to qualify for additional credit.
>50%: Severe financial strain. Most income is consumed by debt payments.

Improving DTI: pay down balances (lowers the numerator), increase income (raises the denominator), or both.

Balance transfer strategy

A 0% APR balance transfer credit card can accelerate payoff by eliminating interest accrual during the promotional period (typically 12–21 months). Key points:

Transfer fee: Usually 3–5% of the transferred amount. Example: $10,000 balance × 3% = $300 fee.
Payoff math: If you can pay off the balance before the 0% period ends, you save the original card's interest minus the transfer fee.
Example: $10,000 at 20% APR would cost ~$2,000 in interest over 1 year. Transfer fee = $300. Net savings: $1,700.
Caution: After the 0% period, the new card's regular APR (often 18–24%) kicks in. If you haven't paid the balance, you're back to high-interest debt.

Psychological aspects of debt payoff

Snowball method wins on motivation: Research (Dave Ramsey's studies, Harvard Business School) shows that paying off small balances creates "quick wins" that boost motivation and lead to better long-term compliance, even though the avalanche method is mathematically optimal.

Debt fatigue: Large balances with high interest feel insurmountable. Tracking progress month-by-month (e.g., "Paid $500 principal this month!") keeps motivation high.

Avoiding new debt: Cut up high-interest cards (keep the account open for credit score, but remove the temptation). Use debit or cash-only until debt is cleared.