Snowball months
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Debt Payoff Snowball vs Avalanche Calculator
Compare snowball and avalanche payoff months and interest on two debts plus extra payment.
Page updated 2026-09-04.
Calculator
Calculated Results
Avalanche months
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Snowball interest
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Avalanche interest
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Snowball and avalanche, run on the same two debts
With an $8,000 balance at 22% APR and a $4,000 balance at 9% APR, both carrying their stated minimums plus $150 extra a month, snowball (smallest balance first) clears both debts in 43 months and costs $4,549.02 in interest. Avalanche (highest rate first) clears them in 41 months for $3,286.88 in interest -- two months faster and about $1,262 cheaper, because the extra payment attacks the 22% balance before the 9% one.
That gap is the whole argument for avalanche on paper. Snowball's case is behavioral: closing the smaller $4,000 balance first gives a win sooner, which is why some people stick with a plan longer even though it costs more in interest.
The simulation runs month by month rather than using a shortcut formula: each month it applies the rate to the remaining balance, pays the minimum on every open debt, and routes the extra payment plus any freed-up minimum toward whichever debt the strategy prioritizes.
A two-debt model, not a full payoff plan
Every balance and minimum payment must be greater than zero, and the simulation caps out at 600 months -- if your numbers can't clear both debts inside 50 years, the page flags it rather than looping indefinitely.
Two-debt model with a fixed extra payment. Not credit counseling. If you're carrying more than two balances, add a third by running this twice: pay off the smaller pair first, then treat the freed-up minimums as new extra payment on the third.
For a single lump-sum loan instead of a payoff race between two balances, the Personal Loan Payoff Calculator is the simpler version of this math.
Before you commit to a strategy
If a 0% balance-transfer offer is on the table, that changes the math entirely -- check the Credit Card Balance Transfer Savings Calculator before running snowball or avalanche against a rate you might be able to reset to zero.
Once both debts are gone, the Debt-to-Income Ratio Calculator shows how much that freed-up minimum payment improves your borrowing position.
Frequently Asked Questions (FAQ)
Why does avalanche beat snowball by only 2 months here but save over $1,200?
Because the rate gap (22% vs. 9%) is large relative to the balance gap. Avalanche's time savings shrinks or disappears entirely when the higher-rate balance is also the larger one, but the interest savings from targeting the highest rate first is almost always positive.
What if I have more than two debts?
This page models exactly two. Group additional debts into a third pass -- clear the pair here, then apply the combined minimum plus extra payment to the next debt in line using the same strategy.
What happens if a balance or minimum payment is left blank or zero?
The calculator returns a validation message instead of a result, since a $0 minimum would mean the debt never gets paid down. Both debts need a real balance and a real minimum to run the simulation.
Is this credit counseling or a debt management plan?
No. It's a two-debt interest simulation, not credit counseling. If you're behind on payments or considering settlement, that's a conversation for a nonprofit credit counselor, not this calculator.
Does raising the extra payment change which strategy wins?
It narrows the gap. A larger extra payment clears both debts faster under either strategy, which shrinks the number of months avalanche's rate-targeting has to compound its advantage -- so the dollar savings from choosing avalanche over snowball gets smaller as the extra payment grows.
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