The Debt Payoff Calculator: Run Your List Both Ways, With 2026 Rates and Your Own Budget

You have the list and a number to spend on it. That is a better starting position than most advice assumes — the debt is known, the budget is set, and the only open question is the order. This calculator takes the same four-debt, $25,000 list the avalanche-vs-snowball article runs to maturity, keeps the dated 2026 rates, and lets you move the budget. Both orders come out: the month the last line hits zero, the interest you carry to get there, and the difference between them, on your numbers. The payoff order is the decision. The rest of the page is the arithmetic of it, shown.

If you have not read the companion article, the two orders in one line each: the avalanche is the rate order — highest APR first, everything else last. The snowball is the balance order — smallest balance first, everything else last. The companion runs one fixed schedule and lays out what each order is worth, counted; this page is the same question with your budget on the input side. And if you came looking for a debt snowball spreadsheet: this is that, without the download — the box below runs the same arithmetic, and the block before it is the formula for every cell you would have written.

The inputs

Thirteen numbers: four balances, four rates, four payments, one budget. Nothing else goes into the machine.

The defaults loaded into the box are the companion’s list, and every rate in it is a published number from one dated source. The Federal Reserve’s G.19 Consumer Credit release, dated September 8, 2026, carries the second-quarter 2026 averages: 22.15 percent on credit-card accounts assessed interest, 20.94 percent on all card accounts, 11.86 percent on 24-month personal loans, 7.14 percent on 60-month new-car loans. The $25,000 list:

Swap in your own four lines; the arithmetic does not care where your rate came from, only that you used yours. One dated note on the rates, because card rates are variable: card APRs follow the prime rate — one of the base rates the biggest banks post, in the release’s own words — and the Federal Reserve’s H.15 release had the bank prime loan rate at 7.00 percent on every day it lists for the last week of September 2026, in the release dated October 2, 2026. If your card’s rate moves mid-schedule, the schedule gets re-run. That is the dated-schedule rule: the numbers are the numbers of a date, and the date is stated.

The formulas, shown

The whole model fits in one block. If you can read it, you can run the calculator by hand on a spreadsheet — and check any box that claims to be one.

for each open debt:
  interest   = balance x (APR / 12)
  balance    = balance + interest - the debt's payment
extra        = budget - the payments of the debts still open
the extra goes to the first open debt in the chosen order:
  avalanche  = highest APR first
  snowball   = smallest balance first
when a debt hits zero, its payment becomes extra
repeat until every balance is zero

Three stated conventions. Interest is computed on the balance before that month’s payment is applied, so month one on $6,000 at 22.15 percent is $110.75. Rounding happens once, on each month’s interest, to the cent. And the budget stays whole: when the auto loan’s $50 is paid off, the fifty does not evaporate — it joins the extra, and the outflow never drops below your budget. That last convention is the whole argument of the companion article in schedule form — “the payment never changes; only the order does” — and there is a section below that reconciles what it prints against the fixed table in that article.

The calculator

The box is the formula block with a field on each input. If it renders as an empty frame in an old browser, nothing is lost that the printed math does not already carry — the noscript line inside it runs the worked example in ink.

The worked output

One set of inputs — the defaults — and both orders, run to zero. Every number below is what the box prints at these inputs, and you can check any of them against the printed block. The calendar names are counted from the first payment, October 2026; the box counts them from the month you open it in.

The delta at these inputs: the balance order costs $981.47 more and lands one month later. Read the first row before the totals, because it is the whole trade laid out. The snowball buys its first win seven months sooner — April 2027 against November 2027 — and pays for it across the two cards. That is the companion article’s disagreement, on a calculator: the rate is the number that decides the interest; the first win is the number that decides whether you are still there in month fifteen.

One reconciliation, stated straight. The companion article’s fixed schedule prints 41 months and $6,139.26 under the avalanche, 39 and $7,217.76 under the snowball. Those totals come from a schedule whose outflow shrinks as debts die — when the first card is gone at month 14, its $180 stops leaving the household instead of becoming extra. This calculator pays the promise that article makes in words — the payment never changes; only the order does — so the freed payments keep running, and both orders land sooner and cheaper on the same list. The first wins match exactly (month 14, month 7); the totals part company wherever a payoff frees money. Same debts, same rates, two schedules, one of them keeping its budget whole. Put your own list in the box and the model it runs is the formula block above, with nothing else inside.

What the order is worth, at your budget

The order is not worth a fixed amount. It is worth exactly what your extra is worth. Same $25,000 list, same dated rates, six budgets — every row recomputed by the box’s own arithmetic:

Read the top row first. With nothing but the four listed payments and no extra, the two orders finish in the same month and cost $2.71 apart — a rounding error, because there is barely any money for the order to point anywhere. The order is the steering, and a parked car does not steer. Then read the bottom row: at $2,000 a month both orders land the same month, and the avalanche still buys $528.99 — the order buys money, and only sometimes buys time. Between those two ends is where the debate in the companion article actually lives: at $800, the balance order buys its first win nine months sooner (month 15 against month 24) and costs $998.97 for it; at $1,000 the price is $981.47 and one month of time. The rate is the number that decides the interest; the budget line decides how much that deciding is worth.

The minimum-payment floor

Every payoff schedule starts from a payment line, and on a card that line has a floor — partly set by the card, partly by the rule on your statement. Regulation Z, the Truth in Lending rule at 12 CFR 1026.7, requires every credit-card statement to carry this sentence, verbatim, with a bold heading: “Minimum Payment Warning: If you make only the minimum payment each period, you will pay more in interest and it will take you longer to pay off your balance” — followed by an estimate of the years and the total interest that follows from exactly that assumption, and the note that the estimate holds only if no new charges go on (the rule as published in the eCFR, title 12 current as of October 1, 2026).

Run the assumption on the two cards in the default list — minimums only, 3 percent of the current balance with a $25 floor, nothing new charged:

• Card 1, $6,000 at 22.15 percent: 215 months — close to eighteen years — and $8,356.08 of interest on $6,000 of debt.
• Card 2, $9,000 at 20.94 percent: 232 months and $11,325.87 of interest on $9,000.

That is $19,681.95 of interest on the $15,000 of card debt in the list — more than the cards owe, counted slowly. And the floor has a cliff beside it. A flat $25 minimum beats the interest only while the monthly interest stays under $25 — at 22.15 percent that caps the balance near $1,354; above it, the interest alone is more than the payment. Put a $2,000 balance at that rate on a flat $25 minimum and the first month’s interest is $36.92 against the $25 that arrives. The balance does not fall; it climbs — $5,150.95 more of it after ten years. A line that runs uphill is not the order’s problem; it is the payment’s. The box above flags it when you enter one.

This is why the calculator’s payment lines are inputs and not floors. The minimum is the number the card sends you; the payment is the number you decide; the budget is the number that decides both.

Which order, on your numbers

The recommendation logic, in the order it actually gets used.

1. Run the box at your real budget. Not the one you wish you had. The table above says the order’s price runs from two-seventy-one to nearly a thousand dollars across realistic budgets — a few hundred to one; run yours.
2. Compare the two output lines the way they print. If the interest gap is money you can feel — four figures, say — and you are confident you will send the money for thirty-plus months, the rate order is the math, and the math is on your side.
3. Compare the first-win line next. If your last plan died somewhere around month fifteen with nothing paid off yet, the balance order’s earlier first win is not a trick — it is the thing that buys you the thirty-first month. The avalanche is the math; the snowball is the follow-through. The plan you finish is the plan that counts.
4. If the budget is at or near the sum of the payments, decide by anything except the order. At $666 the choice is worth $2.71. The fight worth having is over the extra, not the sequence.
5. And if a line grows — payment under interest — no order applies yet. Raise that payment or stop borrowing on that line first.

The list, the orders, the budget, the one you finish — that is the whole decision. What the money behind the schedule is: the reserve that lets a payoff schedule survive a blown tire is sized in the emergency fund calculator next door, and the avalanche-vs-snowball article carries both full schedules, the per-debt interest and the research on why the smaller first win moves people.

List them, pick the order, start.