Debt Payoff Calculator

Compare the avalanche and snowball debt payoff methods side by side on your own balances: total interest, payoff time and the order each method clears your debts. Runs entirely in your browser — your numbers never leave this device.

Debt nameBalance ($)APR (%)Minimum ($/mo)

Debt 2 nameBalance ($)APR (%)Minimum ($/mo)

Extra payment per month$

Payoff strategy

Debt-free in

29 months (2 yrs 5 mos)

Avalanche: extra money attacks the highest APR first, which minimises total interest.

Debt-free in: 29 months (2 yrs 5 mos)
Total interest: $993.70
Total paid: $5,993.70

Payoff order

Card — cleared in month 24
Loan — cleared in month 29

Per-debt breakdown

Debt	Cleared	Interest paid
Card	Month 24	$797.81
Loan	Month 29	$195.89

How it works

Each month: pay every debt's minimum, then put all remaining budget on one target debt | Avalanche target: highest interest rate | Snowball target: smallest balance | Interest that month on each debt = balance × (APR / 1200)

With several debts and one monthly budget, the only real choice is the order of attack. This calculator simulates the same debts, the same budget and the same minimum payments under both standard strategies, month by month: interest accrues on every balance, every minimum is paid, and whatever budget remains is thrown at one target debt until it clears, then rolls on to the next. The output is the payoff time, the total interest and the clearing order for each strategy.

The avalanche method targets the highest interest rate first. This is mathematically optimal: expensive debt is the debt growing fastest, so killing it first always produces the lowest possible total interest for a given budget — no other ordering can beat it on cost. The snowball method targets the smallest balance first, which clears a debt completely sooner and reduces the number of separate bills, at the price of letting a larger high-rate balance run for longer.

Neither result is spun. The calculator prints both interest totals — including when they are close, which happens whenever the smallest debt also carries a high rate or the budget is large relative to the balances. The honest reading is that avalanche wins on money and snowball can win on motivation: a strategy abandoned after two months costs more than either strategy followed to the end. The numbers are here so the choice is made with the price of each approach visible.

Worked examples

Two cards, $250 a month: the methods compared

Input: Card A = $800 at 8% APR (minimum $25), Card B = $5,000 at 22% APR (minimum $100), Total budget = $250/month
Working: Minimums consume $125, leaving $125 of extra budget. Avalanche points the extra at Card B (22%): Card B clears first, then Card A; simulation gives 30 months and $1,579.66 total interest. Snowball points the extra at Card A ($800, smallest): Card A clears first, then Card B; simulation gives 31 months and $1,772.56 total interest.
Result: Avalanche: 30 months, $1,579.66 interest. Snowball: 31 months, $1,772.56 interest. Avalanche saves $192.90 here

Why the first month looks similar under both

Input: Same debts as example 1, month 1 only
Working: Interest in month 1 is fixed by the balances: Card A charges 800 × (8/1200) ≈ $5.33 and Card B charges 5,000 × (22/1200) ≈ $91.67, total ≈ $97.00, whichever strategy you choose. The strategies diverge over time because the extra $125 reduces different balances, changing every later month's interest — the difference is earned gradually, not in month 1.
Result: Month 1 interest ≈ $97.00 under both methods; the gap opens in later months

When both methods give the same answer

Input: Single debt, or several debts where the smallest balance also has the highest rate
Working: If the smallest balance is also the highest-rate debt, the avalanche target and the snowball target are the same debt, so both simulations follow the identical path and report identical months and interest. With only one debt there is no ordering decision at all — the whole spare budget goes to that debt under either label.
Result: Same target debt means same payoff time and same total interest under both names

Frequently asked questions

Is avalanche always cheaper than snowball?

Yes, on interest — that is a mathematical property, not a matter of opinion: directing spare money at the highest rate first minimises the total interest any fixed budget can achieve. In the worked example the saving is ≈ $240.09 and one month. What avalanche does not guarantee is speed to the first cleared debt, which is where snowball has its one genuine advantage.

Why do people choose snowball if it costs more?

Because clearing a small debt completely — one fewer bill, one account closed — is motivating, and a plan followed to the end beats a cheaper plan abandoned early. The honest way to decide is with the price in front of you: this calculator shows exactly how many dollars the motivational advantage costs on your actual balances, which is sometimes small enough to be worth paying.

What happens to a cleared debt's minimum payment?

It rolls into the attack budget — that rolling effect gives both methods their names' imagery. If a $25 minimum is freed when a card clears, the extra aimed at the next target grows by $25 a month, so debts fall progressively faster. The simulation in this calculator includes the roll automatically.

Should I include every debt I have?

Include every debt the budget genuinely covers: cards, personal loans, store finance and similar. Mortgages are usually planned separately because of their size and term, but nothing in the maths prevents adding one — just expect its low rate and large balance to sit last in the avalanche order and its size to dominate the snowball timeline.

What if my budget only just covers the minimums?

Then there is no spare amount to direct, both strategies behave identically, and the payoff follows the minimum-payment path — which, on card balances, can take many years (the Credit Card Payoff Calculator shows how extreme that path gets). Even a small amount above the minimums creates a real difference, because it all lands on one balance.

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