Debt payoff calculator — snowball vs avalanche
Compare the snowball and avalanche methods across all your debts: payoff order, monthly plan, interest paid and time saved.
- Runs in your browser
- Nothing you enter is sent
- Free, no account
Total owed today
$16,400.00
Monthly budget
$610.00
$410.00 minimums + $200.00 extra
Total interest
$2,633.79
Total paid
$19,033.79
weighted APR 12.94%
- Avalanche interest · 2 years 8 months$2,633.79
- Snowball interest · 2 years 8 months$2,633.79
Avalanche saves
$0.00
in interest, versus snowball
Difference in time
None
both finish in the same month
First win — snowball
6 months
Store card
First win — avalanche
6 months
Store card
- Avalanche (highest APR first)
- Snowball (smallest balance first)
| Order | Debt | Balance | APR | Interest paid | Cleared |
|---|---|---|---|---|---|
| 1 | Store card | $1,200.00 | 26.9% | $89.31 | Jul 2026 |
| 2 | Credit card | $5,400.00 | 19.9% | $1,349.17 | Jan 2028 |
| 3 | Car loan | $9,800.00 | 7.4% | $1,195.31 | Sep 2028 |
Formula and working
Monthly budget
Budget = Σ minimum payments + extra = 410 + 200 = $610.00
Interest on one debt, one month
Interest = balance × (APR ÷ 12) Store card: 1,200 × 0.022417 = $26.90 Credit card: 5,400 × 0.016583 = $89.55 Car loan: 9,800 × 0.006167 = $60.43 = $176.88
The rollover
target payment = budget − Σ minimums on the other open debts month 1: $610.00 − $375.00 of other minimums when a debt clears, its minimum is not spent — it joins the pot for the next debt = 3 debts cleared in 2 years 8 months
Cost of choosing snowball
extra interest = snowball interest − avalanche interest = 2,633.79 − 2,633.79 = $0.00
Order is decided once, from today's balances, and then held. Re-sorting every month barely changes the total and makes the plan impossible to follow.
| # | Month | Paid | Interest | Total owed |
|---|---|---|---|---|
| 1 | Feb 2026 | $610.00 | $176.88 | $15,966.88 |
| 2 | Mar 2026 | $610.00 | $170.62 | $15,527.50 |
| 3 | Apr 2026 | $610.00 | $164.24 | $15,081.74 |
| 4 | May 2026 | $610.00 | $157.74 | $14,629.48 |
| 5 | Jun 2026 | $610.00 | $151.10 | $14,170.58 |
| 6 | Jul 2026 | $610.00 | $144.36 | $13,704.94 |
| 7 | Aug 2026 | $610.00 | $138.18 | $13,233.12 |
| 8 | Sep 2026 | $610.00 | $132.56 | $12,755.68 |
| 9 | Oct 2026 | $610.00 | $126.87 | $12,272.55 |
| 10 | Nov 2026 | $610.00 | $121.10 | $11,783.65 |
| 11 | Dec 2026 | $610.00 | $115.24 | $11,288.89 |
| 12 | Jan 2027 | $610.00 | $109.30 | $10,788.19 |
Showing 1–12 of 32 rows
Assumptions
- Interest is charged once a month on the balance carried into the month, then payments are applied. Cards that use a daily periodic rate will differ slightly.
- Minimum payments are held constant at the figure you enter. Real card minimums fall as the balance falls, which makes the do-nothing case worse than modelled here — the extra payment is what does the work either way.
- No new borrowing, no fees, no promotional-rate expiry and no rate changes are modelled.
- The payoff order is fixed from today’s balances and APRs; a debt is only ever paid its minimum until it becomes the target.
- Everything you type stays in this browser tab. Turning on the save switch writes the list to this device’s local storage only, and the delete button removes it immediately.
Two orders, one engine
Snowball and avalanche are not different budgets. They are the same budget applied in a different order. In both, you pay the minimum on every debt and throw everything else at one target. When that target clears, its minimum joins the pot and the whole payment rolls onto the next one. The only question is which debt goes first.
- Avalanche targets the highest APR first. It always costs the least interest, because you are killing the most expensive money first.
- Snowball targets the smallest balance first. It costs more, sometimes only slightly, but it produces a cleared debt sooner — and a cleared debt is what keeps people going.
The comparison above runs both against your actual debts and reports the exact gap. That gap is the price of the psychological win, and it is the only honest way to choose.
Why the rollover matters more than the order
The order changes the total by a few per cent. The rollover changes it by an order of magnitude. Consider three debts with minimums of 35, 110 and 265 and an extra 200 a month:
| Stage | Payment at the target debt |
|---|---|
| All three open | 200 + its own minimum |
| After the first clears | 200 + 35 + its own minimum |
| After the second clears | 200 + 35 + 110 + its own minimum |
By the last debt, the whole 610 monthly budget is aimed at a single balance. This is why payoff plans accelerate so dramatically towards the end, and why abandoning the plan halfway — by absorbing a freed-up minimum back into spending — destroys most of the benefit.
Fixing the order, and why
The payoff order is decided once, from today's balances and rates, and then held for the whole plan. Re-sorting every month as balances change produces a marginally different total and an unfollowable plan. A debt plan is a behavioural instrument as much as a financial one: if you cannot write it on an index card, it will not survive month four.
What to include, and what to leave out
- Include: credit cards, store cards, overdrafts, personal loans, car finance, buy-now-pay-later balances and anything at a rate above what savings earn.
- Leave out a low-rate mortgage. Under avalanche it will sort last and sit there for decades, dominating the schedule without informing anything. Model it separately with an amortization schedule.
- Think carefully about student loans. Income-contingent systems (UK Plan 2, US IDR plans) behave nothing like a fixed instalment loan, and overpaying can be actively wasteful if the balance will be written off.
- Build a small emergency buffer first. Clearing a card and then re-borrowing on it after a car repair is a net loss. One month of expenses in cash is usually the right thing to do before the plan starts.
Reading the month-by-month plan
The plan table is the artefact worth printing. Each row is one month: what you paid in total, how much of it was interest, how much of the debt actually disappeared, and what remains. The milestone column marks the months a debt clears — those are the rows to circle, because they are the ones that keep the plan alive.
Where the numbers come from
Each month the simulation charges interest on every open balance at its own monthly rate (APR ÷ 12), pays the stated minimum on every debt except the target, then applies everything remaining in the budget to the target. Balances are held as arbitrary-precision decimals and rounded to the minor unit at each interest charge, the way a card statement does it. If the budget cannot outrun the combined interest, the calculator says so rather than silently producing a fifty-year plan.
Nothing leaves this tab, and nothing is stored by default
A list of your debts with balances and rates is about as sensitive as personal finance data gets. There is no server behind this page and no analytics on it, so the list has nowhere to go. Saving is off unless you turn it on; when you do, it writes to this browser's local storage on this device only, and the delete button beside the switch removes it immediately. You can work through the whole plan with the network disconnected.
Questions
What is the difference between snowball and avalanche?
Snowball attacks the smallest balance first for a quick psychological win. Avalanche attacks the highest APR first, which always costs less in interest. Both pay the minimum on everything else and roll each cleared minimum onto the next debt.
Which one should I use?
Avalanche is mathematically better — this page shows exactly how much better for your debts. Snowball wins in practice for people who need an early visible win to keep going. If the gap is small, pick the one you will actually finish.
What is the rollover?
When a debt clears, its minimum payment does not go back into your spending. It joins the pot attacking the next debt in the order, so the payment aimed at each successive debt grows — that is the "snowball" effect, and avalanche uses it too.
Does this save my debts?
Only if you switch it on. Saving is off by default and writes to your browser’s local storage on this device only, with a delete button next to the switch. Nothing is ever uploaded.
Should I include my mortgage?
Usually not. A payoff plan is designed for high-rate consumer debt. A low-rate mortgage in the same list will dominate the order under avalanche and distort the plan — model that separately with the amortization schedule.