Snowball vs Avalanche Calculator: Side-by-Side Comparison
This page's hero is the dual-plan comparison table: the same debts and budget run under both strategies, plus hybrid and a minimums-only baseline. For the full planner experience, open the Debt Payoff Planner.
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Disclaimer
Not financial advice. This calculator is for educational purposes only and is not financial advice, tax advice, or a recommendation. Consider speaking with a qualified professional about your situation.
Assumptions. Interest is calculated monthly as balance × APR ÷ 12 and applied before each payment (monthly compounding). If you leave a minimum payment blank, it is estimated as the largest of: 2% of the balance, one month's interest + 1% of the balance, or $25 — actual minimums vary by lender. Simulations stop at 600 months. Displayed amounts are rounded to the nearest cent.
Data sources. Formulas: standard amortization math. No external data feeds. Page last updated: 2026-10-18.
How the math works
This page runs four payoff plans on identical inputs and puts the outcomes in one table: snowball, avalanche, hybrid, and a minimums-only baseline. The columns are the debt-free date, the number of monthly payments, total interest, total paid, and interest saved versus the baseline. Because debts, budget, start month, extras, and lump sums are held fixed across the rows, every difference in the table traces back to the payment order.
The ordering rules behind the rows are simple. Snowball aims each month's extra money at the smallest remaining balance, ties broken by higher APR. Avalanche aims it at the highest APR, ties broken by smaller balance. Hybrid starts in snowball order and switches to avalanche order once the unpaid count reaches K or below; K is adjustable from 1 to 10 with a default of 3. Each ordering is recomputed monthly from the balances carried into that month, and cleared debts leave the ordering. The snowball calculator and avalanche calculator pages walk through each rule separately.
The baseline row is computed differently on purpose: it pays only each debt's minimum every month, with no extras, no lump sums, and no cascade — unspent differences are simply not paid — so the strategy plays no role in it. Interest saved equals baseline total interest minus plan total interest. If the baseline never clears the balances within the simulation limit, that column shows n/a instead of a number, because there is no baseline interest total to subtract from.
Rows can look identical, and that is informative rather than broken. A single debt makes every strategy target the same balance. A budget that barely covers the minimums leaves almost no extra money to redirect, so order changes little. When K is greater than or equal to the debt count, hybrid behaves as avalanche from month one. Visible gaps open up when extra payments are large and the debts' APRs differ widely.
Within each plan the monthly loop is the same: interest first at balance times APR divided by 12, then minimums — entered, or estimated as the largest of 2% of the balance, one month's interest plus 1% of the balance, or $25 when blank — then extras, then the remainder cascading down the priority order. Lump sums land on the current month's target first. When the budget falls short of total minimums, minimums are scaled proportionally and the shortfall is reported as a plain number.
The simulation rests on four stated assumptions. One: interest compounds monthly — balance times APR divided by 12, applied before payments. Two: when a minimum is left blank it is estimated as the largest of 2% of the balance, one month's interest plus 1% of the balance, or $25, capped at the balance — an industry-typical approximation, not any lender's exact formula. Three: every simulation stops at 600 months, even if balances remain. Four: all internal math uses full double precision with no per-month rounding; displayed amounts are rounded half-up to the nearest cent after totals are computed.
One limitation to know: the engine uses the nominal APR divided by 12 as the monthly rate, which matches the standard US credit-card convention. Loans that accrue with a daily periodic rate produce slightly different month-to-month figures.
Worked example
Inputs: Debt A, balance $3,000, APR 24.99%, minimum $60 (entered); Debt B, balance $1,500, APR 12%, minimum $40 (entered); monthly budget $400. Total minimums are $100, leaving a $300 remainder to aim each month. Month 1 interest is added before any payment: A accrues $3,000 × 0.2499 ÷ 12 = $62.475 (displayed $62.48), B accrues $1,500 × 0.12 ÷ 12 = $15.00.
| Plan | Target | A end balance | B end balance | Month-1 total interest |
|---|---|---|---|---|
| Snowball | B (smallest balance) | $3,002.48 | $1,175.00 | $77.48 |
| Avalanche | A (highest APR) | $2,702.48 | $1,475.00 | $77.48 |
Under snowball, B receives its $40 minimum plus the $300 remainder: $1,515.00 − $340.00 = $1,175.00; A ends at $3,062.475 − $60.00 = $3,002.475, displayed $3,002.48. Under avalanche, A receives its $60 minimum plus the $300 remainder: $3,062.475 − $360.00 = $2,702.475, displayed $2,702.48; B ends at $1,515.00 − $40.00 = $1,475.00. Month-1 total interest is identical ($77.48) in both rows because interest accrues before payments; the strategies diverge as the differing balances compound over later months. With K = 3 and only two debts, the hybrid row behaves as avalanche from month one. The tool above runs all four plans to completion on your own numbers.
Frequently asked questions
What does the comparison table show?
Four plans computed from the same debts, budget, start month, and what-if settings: snowball, avalanche, hybrid, and a minimums-only baseline. Columns list the debt-free date, months, total interest, total paid, and interest saved versus the baseline, so every difference between rows comes from the payoff order alone.
Can snowball ever cost less interest than avalanche?
No, not at a fixed monthly budget. Because avalanche aims all extra money at the highest APR first and interest accrues as balance times APR divided by 12, its total interest is always less than or equal to snowball's on identical inputs. The table shows the exact gap for your numbers.
Why are the payoff months sometimes identical across plans?
When the budget barely covers the minimums there is almost no extra money to redirect, so order matters little. A single debt also makes every plan identical. Larger extra payments and bigger rate spreads between debts are what open up visible gaps between the rows.
What is the minimums-only baseline?
It is a reference plan that pays each debt only its minimum every month, with no extras, no lump sums, and no cascade of leftover money; unspent differences are simply not paid. The strategy plays no role in it, which keeps the baseline identical no matter which strategy is selected.
What does n/a mean in the interest-saved column?
It means the minimums-only baseline does not clear the balances within the 600-month simulation limit, so there is no baseline total interest to compare against. The plan rows still show their own debt-free dates, months, and total interest where they reach zero.
The table shows no recommendation. How do I read it?
Each row is the arithmetic outcome of one ordering rule applied to your inputs. The interest and date columns let you compare the trade-off directly: the avalanche row shows the lowest total interest at this budget, while the snowball row shows the smallest-balance-first path.