Debt Avalanche Calculator
Enter every balance, its rate and its minimum against one monthly budget: this debt avalanche calculator sends everything above the minimums to the highest rate first and returns the debt-free date, the total interest and the month each debt closes.
Debt-free September 1, 2028 after 24 months
- Months to debt-free
- 24
- Total interest
- $1,785.39
- Total paid
- $14,285.39
Payoff order
- 1 Credit card August 2027
- 2 Car loan August 2028
- 3 Store card September 2028
Month-by-month plan — every month, every balance
| # | Date | Store card | Credit card | Car loan | Paid | Interest |
|---|---|---|---|---|---|---|
| 1 | 2026-10-01 | $1,470.00 | $3,670.00 | $6,920.00 | $600.00 | $160.00 |
| 2 | 2026-11-01 | $1,439.80 | $3,333.40 | $6,839.20 | $600.00 | $152.40 |
| 3 | 2026-12-01 | $1,409.40 | $2,990.07 | $6,757.59 | $600.00 | $144.66 |
| 4 | 2027-01-01 | $1,378.80 | $2,639.87 | $6,675.17 | $600.00 | $136.78 |
| 5 | 2027-02-01 | $1,347.99 | $2,282.67 | $6,591.92 | $600.00 | $128.74 |
| 6 | 2027-03-01 | $1,316.98 | $1,918.32 | $6,507.84 | $600.00 | $120.56 |
| 7 | 2027-04-01 | $1,285.76 | $1,546.69 | $6,422.92 | $600.00 | $112.23 |
| 8 | 2027-05-01 | $1,254.33 | $1,167.62 | $6,337.15 | $600.00 | $103.73 |
| 9 | 2027-06-01 | $1,222.69 | $780.97 | $6,250.52 | $600.00 | $95.08 |
| 10 | 2027-07-01 | $1,190.84 | $386.59 | $6,163.03 | $600.00 | $86.28 |
| 11 | 2027-08-01 | $1,158.78 | $0.00 | $6,058.98 | $600.00 | $77.30 |
| 12 | 2027-09-01 | $1,126.51 | $0.00 | $5,559.57 | $600.00 | $68.32 |
| 13 | 2027-10-01 | $1,094.02 | $0.00 | $5,055.17 | $600.00 | $63.11 |
| 14 | 2027-11-01 | $1,061.31 | $0.00 | $4,545.72 | $600.00 | $57.84 |
| 15 | 2027-12-01 | $1,028.39 | $0.00 | $4,031.18 | $600.00 | $52.54 |
| 16 | 2028-01-01 | $995.25 | $0.00 | $3,511.49 | $600.00 | $47.17 |
| 17 | 2028-02-01 | $961.89 | $0.00 | $2,986.60 | $600.00 | $41.75 |
| 18 | 2028-03-01 | $928.30 | $0.00 | $2,456.47 | $600.00 | $36.28 |
| 19 | 2028-04-01 | $894.49 | $0.00 | $1,921.03 | $600.00 | $30.75 |
| 20 | 2028-05-01 | $860.45 | $0.00 | $1,380.24 | $600.00 | $25.17 |
| 21 | 2028-06-01 | $826.19 | $0.00 | $834.04 | $600.00 | $19.54 |
| 22 | 2028-07-01 | $791.70 | $0.00 | $282.38 | $600.00 | $13.85 |
| 23 | 2028-08-01 | $482.18 | $0.00 | $0.00 | $600.00 | $8.10 |
| 24 | 2028-09-01 | $0.00 | $0.00 | $0.00 | $485.39 | $3.21 |
What this page tells you
The debt avalanche is an ordering rule, and it governs one number only. Add up the minimum payments on every debt, subtract them from the monthly budget, and what is left is the surplus — the avalanche puts all of it on the debt with the highest interest rate, then on the next highest, until nothing is left owing. The minimums go on being paid to every open debt the whole time, including the one at the bottom of the order. What the method changes is where the surplus lands, and nothing else.
Ordering by rate is the arithmetically optimal choice: a dollar against a 24% balance stops twice the interest of the same dollar against a 12% one, so on the same debts, the same minimums and the same budget the avalanche never pays more interest than the snowball. On the three debts below it saves $250.19 and finishes a month sooner. What it costs shows up in the same run — the first debt does not close until month 11, where the snowball closes one in month 5 — and a method nobody keeps to saves nothing. Both plans are printed here rather than argued over, because which of those two figures matters more is not something the arithmetic can see.
The ordering is also the smaller of the two levers. These three debts on their minimums alone — $290.00 a month, nothing above it — take 66 months and $6,377.95 in interest. Raising the budget to $600.00 brings that down to 24 months and $1,785.39 under the avalanche, a difference of $4,592.56, of which the choice of ordering accounts for $250.19. The size of the surplus does most of the work; the ordering decides how much of it is wasted.
How to read the result
The debt-free date is the date of the last payment, counted forward from the first payment date rather than read off a formula. Twenty-four monthly payments beginning 1 October 2026 end on 1 September 2028, because the twenty-fourth falls twenty-three months after the first. Every debt also carries its own payoff month, and under the avalanche the last of them is often the smallest balance on the list — here the $1,500 store card, at the lowest rate, which is still open in month 24.
Only the surplus is ordered. Every open debt is still paid its minimum, including the one at the bottom of the priority list. The store card sits last on these inputs, at 8%, and still receives $40.00 a month against a first month's interest of $10.00, so it falls from $1,500.00 to $1,158.78 by the end of month 11 without ever having been the target. Directing the surplus is the whole of the decision; the minimums are contractual, and the plan on this page assumes every one of them is paid on time.
A freed minimum moves in the month it is freed, not the month after. The credit card ends month 10 owing $386.59, accrues $7.73, and needs $394.32 to close — its own $100.00 minimum and $294.32 of the $310.00 surplus. The $15.68 left over goes to the car loan in that same month, which receives $165.68 instead of its $150.00 minimum. From month 12 the car loan receives $560.00 a month: its minimum, the $310.00 surplus, and the credit card's freed $100.00.
The avalanche can tie with the snowball, and two situations produce a tie. The first is a surplus of zero. Set the budget to $290.00, exactly the minimums, and both methods return an identical plan — 66 months and $6,377.95 of interest — because there is nothing above the minimums to order. The second is when the two orderings name the same debts in the same sequence. Keep these balances but put the 24% rate on the $1,500 card and the 8% on the $7,000 loan, and smallest-balance-first and highest-rate-first agree at every step: both finish in 23 months with $1,202.34 of interest, to the cent.
The last month costs less than the budget. Twenty-three months of $600.00 are followed by a final month of $485.39, because that month only has to clear what is left. The two add to $14,285.39, which is the $12,500.00 owed at the start plus $1,785.39 of interest — the identity the whole plan is checked against at the end.
How the plan is built
- B
- your total monthly budget across every debt
- iₖ
- each debt's interest for month k, rounded half-up to the cent
- bₖ₋₁
- that debt's balance before this month's interest
Each month: interest is added to every open balance, every open debt receives its minimum, and whatever is left of the budget goes to one target debt — the first in the chosen order that is still open.
When a debt closes, it simply stops receiving anything, so its former minimum stays in the budget and reaches the next target in the same month. That is the rollover, and it is a consequence of the rule rather than an extra step.
The rounding rule, the final-payment adjustment and the published test vectors are all on the methodology page.
A worked example
A worked example: $310 a month, sent to the highest rate first
Take a $1,500 store card at 8.000% with a $40 minimum, a $4,000 credit card at 24.000% with a $100 minimum and a $7,000 car loan at 12.000% with a $150 minimum. The minimums come to $290.00, so a $600.00 budget leaves $310.00 a month to direct. Month one charges 1,500.00 × 8 ÷ 1,200 = $10.00 on the store card, 4,000.00 × 24 ÷ 1,200 = $80.00 on the credit card and 7,000.00 × 12 ÷ 1,200 = $70.00 on the car loan, $160.00 in all. The avalanche orders by rate — credit card at 24%, car loan at 12%, store card at 8% — so the surplus goes to the credit card in full: 4,080.00 − 100.00 − 310.00 = $3,670.00. The other two receive their minimums only, which leaves the store card at $1,470.00 and the car loan at $6,920.00.
The credit card loses $336.60 in month two: it accrues $73.40, pays $410.00, and ends at $3,333.40. It reaches $386.59 at the end of month 10. Month eleven accrues 386.59 × 24 ÷ 1,200 = 7.7318, rounded half-up to $7.73, so it owes $394.32 and is closed by its $100.00 minimum plus $294.32 of the surplus. The $15.68 that was not needed does not wait for month twelve — the car loan receives $165.68 that month and ends at $6,058.98. From month twelve the car loan receives $560.00: its own $150.00, the $310.00 surplus and the credit card's freed $100.00.
The car loan ends month 22 at $282.38, accrues $2.82, and closes in month 23 on $150.00 of minimum and $135.20 of surplus. That leaves $274.80 of the month's budget, which goes to the store card — the store card takes $314.80 in month 23 and ends at $482.18. Month 24 accrues $3.21 on it and clears it with a final payment of $485.39, the only month in the plan that costs less than $600.00. Total interest is $1,785.39 and the debt-free date is 1 September 2028.
Run the same three debts on the same $600.00 under the snowball — smallest balance first — and the store card closes in month 5, the credit card in month 15 and the car loan in month 25, for $2,035.58 of interest and a debt-free date of 1 October 2028. The avalanche is one month shorter and $250.19 cheaper, about an eighth of the snowball's interest. What that $250.19 costs is eleven months before anything at all closes rather than five, and a $1,500 balance still open in the final month of the plan.
- The debts
- $1,500 at 8% (min $40); $4,000 at 24% (min $100); $7,000 at 12% (min $150)
- Minimums, budget, surplus
- $290.00, $600.00, $310.00
- Avalanche order
- credit card 24%, car loan 12%, store card 8%
- Debt-free
- 24 months, 1 September 2028
- Total interest
- $1,785.39
- Each debt closes
- credit card month 11, car loan month 23, store card month 24
- Final month
- $485.39, against $600.00 in each of the other 23
- Snowball on the same inputs
- 25 months, 1 October 2028, $2,035.58 of interest
- Avalanche against snowball
- one month sooner, $250.19 less interest
- The same debts on minimums alone
- $290.00 a month, 66 months, $6,377.95, identical both ways
Every figure here is derived from the formula above and checked to the cent against vector V15 / V14 in the published test vectors — not read back off this page.
What this does not model
- The plan assumes every dollar above a minimum reaches the debt it is aimed at, in the month it is sent. A lender that treats it as an advance on the next instalment leaves that balance where it was — and the ordering then stops mattering, because snowball, avalanche and paying the minimums all return the same answer. Ask for extra payments to be applied to principal, in writing.
- Interest is charged once a month on each debt's outstanding balance. There is no daily accrual and no compounding within the month, so an issuer that compounds daily will charge a little more than this plan shows. Fees, annual charges, late charges and promotional rates are not modelled either.
- Each minimum is a fixed amount for the length of the plan. A card's real minimum is usually a percentage of the balance and falls as the balance does, which makes a fixed minimum slightly optimistic for any debt that is not yet the target; the credit card page models the percentage rule instead.
- The order is fixed at the start from the starting rates and balances and does not re-sort as balances fall. Every rate is also fixed for the length of the plan, so a promotional rate ending or a variable rate moving — either of which would change the right order mid-plan — is outside what this page computes.
- The budget is the same every month, and nothing new is borrowed against any of these balances while the plan runs. New spending on a card that is still open is the usual reason a real plan takes longer than the one on this page.
- Nothing typed here is transmitted. There are no accounts and no saved plans; the calculation runs in your browser, and the only thing that ever leaves it is the link you choose to copy — balances, rates, minimums and the budget, never the labels.
When to use a different page
One loan or several, fixed payment or revolving — that is the real question behind this family of calculators, and it decides which page answers yours.
Debt snowball
The same engine with the other ordering: smallest balance first, chosen for the order in which debts disappear rather than for the interest. On these three debts it closes the first one in month 5 instead of month 11, and costs $250.19 and a month for that.
Debt payoff planner
Both orderings run side by side on the same debts, with each debt's payoff month under each. Start there while the choice is still open; this page has already made it.
Credit card payoff
One revolving balance rather than several, with the issuer's minimum rule modelled properly — a minimum that shrinks as the balance falls, which is why $5,000 at 24% takes 234 months to clear on minimums alone. The avalanche usually puts a card first, and that page is what a single card looks like on its own.
Debt payoff
The plainer version of the question: how long several balances take in total on a given monthly payment, with one debt-free date and one interest figure rather than a comparison of methods.
Questions people ask
How does the debt avalanche method work?
It pays the minimum on every debt each month, then puts the entire remainder of the budget on the debt with the highest interest rate. When that debt reaches zero its minimum stops being spent on it and joins the money going to the next highest rate, in the same month it is freed. The order is set at the start from the starting rates, and the plan ends in the month the last balance clears.
Is the debt avalanche better than the debt snowball?
It is cheaper, which is not the same thing. On the same debts, minimums and budget the avalanche never pays more interest than the snowball, because the surplus always goes where it stops the most interest: on the example below that is $250.19 and one month. The snowball's argument is the other column — its first debt closes in month 5 rather than month 11 — and whether an early closure changes what actually gets paid is not something either calculation can tell you.
How much does the debt avalanche save?
It depends on the spread between the rates and on the size of the surplus, not on the method. At a $600.00 budget these three debts save $250.19 and a month. Raise the budget to $750.00 and both methods finish in 19 months, with the avalanche $189.45 cheaper — more money ordered, a larger interest gap, and no month gained. Set the budget to $290.00, the minimums exactly, and the two plans are identical.
What happens if two debts have the same interest rate?
The avalanche sends the surplus to the smaller balance first, and if the balances are equal too, to whichever debt was entered first. A tie is exact equality — to the thousandth of a percent on the rate, to the cent on the balance — so 15.000% and 15.001% are not a tie. Two balances of $3,000 and $1,200 both at 15% put the $1,200 first, which is also what the snowball would do.
Why do I still pay minimums on the lowest-rate debt?
Because the minimum is what is owed contractually and only the money above it is yours to direct. The store card in the example is last in the order at 8%, and its $40.00 a month against $10.00 of first-month interest still takes it from $1,500.00 to $1,158.78 by the end of month 11. Where a minimum is smaller than that debt's own monthly interest the balance grows until it becomes the target, and the page names the debt rather than letting it pass unremarked.
Does this debt avalanche calculator save my plan?
No. There are no accounts, nothing is stored between visits, and nothing typed is sent anywhere. The address bar is what replaces a saved plan: the balances, rates, minimums and budget are encoded in the link, so a plan can be bookmarked, reopened later or sent to someone else and it recomputes from those numbers. Debt names are never part of the link.