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Debt Avalanche vs Debt Snowball: Run Your Own Numbers First

Moolah IQ··9 min read
#debt-avalanche#debt-snowball#credit-card-debt#debt-payoff
Intelligence Brief

Debt avalanche directs extra payments to the highest interest rate, while debt snowball targets the smallest balance. Compare both using the same monthly budget, then weigh interest costs, payoff dates, and a plan you can sustain.

The short answer: the debt avalanche sends your extra payment to the balance with the highest interest rate, and the debt snowball sends it to the smallest balance. Both keep the required payment going to every other debt, every month, and when one balance reaches zero its payment rolls into the next target. Which one fits you depends on your own balances, rates, minimum payment terms and monthly budget, and on which plan you can keep running for as long as it takes.

How the two methods differ

Both plans begin with the same instruction. Make the required payment on every account, on time, without exception. Then send one budgeted extra amount, the money left for debt after essential expenses and required payments, to exactly one account, and stay on it until it reads zero. That account's payment then rolls into the next one.

The avalanche picks the target by rate: under comparable terms, each extra dollar sent to the higher-rate balance avoids more interest. The snowball picks the target by size, so an account finishes sooner and the list gets shorter. One detail is easy to miss: the avalanche targets the highest-rate balance, but a small balance elsewhere can reach zero first through its own required payments, under either plan. Finishing an account means paying its balance to zero, not closing the card; the account can stay open.

Why splitting extra payments by balance can miss interest savings

If you have never actually chosen between the two methods, you may be doing a third thing: spreading the extra money across every card at once, roughly in proportion to each balance. Researchers who linked the monthly statements of 1.4 million UK credit card borrowers over two years, published in the American Economic Review, called this balance matching. Among people holding two cards, the share of the payment sent to the higher-rate card averaged about 51%, close to what you would expect if interest rates played no part at all. Fewer than 1 in 10 put every dollar above the minimums on the higher-rate card, and the pattern was no smaller when the gap between the two rates reached 15 percentage points or when payments were large. A companion paper found the same pattern in US credit bureau data.

If that matches your statement, nothing is wrong with you. One possible explanation is that prominent balances draw attention. Matching payments to them can feel responsible because every balance falls a little. The fix is one lopsided extra payment aimed at one account.

Gather four columns and one budget

Open your banking app and check that every scheduled payment covers the current minimum on that account, because a late fee or a penalty rate costs real progress. Then write four columns on a sheet of paper or a spreadsheet: account name, current balance, interest rate, and the minimum payment rule exactly as the statement states it. Add one more number: the total you can afford to send to debt each month after essential expenses. It must be at least the sum of the minimums, and it stays the same in both plans, which is what makes the comparison fair.

Then subtract your lowest rate from your highest. That gap, in percentage points, is context rather than a decision rule. In this simplified model, with identical rates and interest-calculation rules, the same total payment and payment timing, and no new charges or fees, both repayment orders have the same total interest and final payoff month. Individual balances may still reach zero in a different order. As the gap widens, a difference can open up, and its size depends on how much balance sits at the high rate, on your payment, and on how long the plan runs. For scale, Federal Reserve data for the second quarter of 2026 puts the average rate on credit card accounts that were assessed interest at 22.15%.

Run both schedules with identical inputs

Build the avalanche schedule first. Each month, charge every balance its interest, pay every minimum, and send the rest to the highest rate. Here is the simplified monthly model from the video, a hypothetical example:

  • A $1,000 balance at 24% annual interest: $1,000 × 0.24 ÷ 12 = $20 of interest for the month.
  • A $100 payment: $1,000 + $20 - $100 = $920 carried into the next month.

Repeat that for each account, updating its balance and its required payment under its own terms as the balance falls. A payment never exceeds what an account owes; anything left over in that month moves to the next target, and when a balance reaches zero its payment rolls to the next highest rate. Then build the snowball schedule with the same balances, rates, minimums and monthly total, sending the extra to the smallest balance instead. A spreadsheet does this month by month, and so does any payoff calculator that lets you choose the order.

Write down three results from each schedule: the total interest paid, the month the first account reaches zero, and the month the last one does. State the assumptions: rates stay where they are, nothing new goes on the cards, every payment lands on time, and interest is charged monthly at the yearly rate divided by 12. Real issuers typically calculate interest daily on your average daily balance, as the Consumer Financial Protection Bureau explains, so the monthly model is an approximation and the results are estimates that move if your rates, payments or minimums move.

Weigh savings, first zero, last zero, and staying power

Put the two schedules side by side. Where rates differ, the avalanche will usually show a lower interest total, and the snowball will often show an earlier first zero. How far apart they sit is your own answer. An economist at James Madison University modeled the trade-off across households in the 2016 Survey of Consumer Finances and estimated that paying smaller balances first raised total interest by about 1.8% to 4.3% for the average household under the study's assumptions. That is a modeled average, not a measurement of your accounts.

The first zero matters for a different reason. If it sits far out, that is a long stretch of paying before anything visibly finishes. The one study on that stretch comes from a debt settlement firm, not from payoff plans run at home: records of 5,943 clients, published in the Journal of Marketing Research. In that program, whole accounts were settled and closed by the firm, and the fraction of accounts closed predicted who completed the program regardless of how small those accounts were, while the dollar balance closed did not, once the count was taken into account. That is an association inside a settlement program, not proof that the snowball causes people to finish at home. Laboratory experiments in the same journal found a similar shape: people worked faster through a task arranged from smallest part to largest, yet given a free choice they picked that ordering least often.

So the comparison is between a plan you finish and a plan you walk away from, because a plan that stops early saves less than its schedule promised. If your saving is small and your first finished account sits far out, taking the early finish is reasonable. If your saving is large and you can hold out for it, the rate order is worth waiting through. If you have started a payoff plan before and stopped, weight that heavily.

A hybrid is also available: clear one small account first, then switch to rate order. Depending on your numbers, it can cost more interest than pure rate order; what it buys is an early finished account, which the settlement study associated with completion, though it did not test this hybrid. The point is to pick the plan that is still running six months from now.

This is education, not financial advice. Your rates, terms and circumstances are your own, and a qualified professional can help with decisions about your specific situation.

Sources

Frequently asked questions

Does the gap between my highest and lowest rate decide which method to use?

No. The gap tells you whether a difference is possible, not how big it is. In this simplified model, with identical rates and interest-calculation rules, the same total payment and payment timing, and no new charges or fees, both repayment orders have the same total interest and final payoff month, even though individual balances may reach zero in a different order. Beyond that, the difference depends on your balances, your payment and the length of the plan.

Will the avalanche always pay off my highest-rate card first?

Not necessarily. The extra money goes to the highest rate, but a smaller balance elsewhere can reach zero earlier through its own required payments. Your two schedules show which account finishes first under each order, and in which month.

Do I have to close a card once its balance reaches zero?

No. The plans only require paying a balance to zero, and the account can stay open. Closing a card is a separate decision with its own trade-offs. The settlement study above involved accounts closed by a firm inside a program, which is a different situation.

What should I do tonight?

Check that every scheduled payment covers the current minimum, write the four columns, and set one budgeted extra payment to go to one account instead of being split by habit. Run both schedules with the same inputs, note the interest total and the first-zero month for each, and choose the plan you can still see yourself running in six months. Then circle the month when the first account will read zero. Use that estimated date as a milestone, and update your plan as your circumstances change.

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