Two methods, one disagreement
Both strategies start the same: pay the minimum on every debt, then aim every spare dollar at a single target until it is dead, then roll that payment onto the next target. The only disagreement is targeting.
The avalanche, which the CFPB calls the highest interest rate method, targets the most expensive debt first. The snowball targets the smallest balance first, rates be damned.
That is the entire technical difference. One sentence each. The interesting question is why a method that is provably more expensive refuses to die, and the answer says something useful about how debt actually gets paid off.
Both methods share one prerequisite worth stating: a real number for the extra payment. Before picking targets, comb the budget for the dollars that will do the attacking. A payoff order with nothing extra to order around is just a list.
The case for the avalanche
The avalanche is just arithmetic. A dollar thrown at a 27% balance saves you 27 cents a year in interest. The same dollar thrown at an 8% balance saves 8 cents. Every month you indulge the cheaper debt while the expensive one compounds, you donate the difference to your card issuer.
Make it concrete. Say you carry a $1,500 store card at 9%, a $4,000 credit card at 27%, and a $9,000 loan at 13%, with $500 a month beyond the minimums. Avalanche sends that $500 at the 27% card immediately. Snowball sends it at the little 9% balance first, leaving the 27% card compounding at full size for the months it takes to clear the small one. The exact cost depends on your numbers, but the direction never changes: snowball pays extra interest, every time the rates and balances diverge.
If you are the kind of person who will run the spreadsheet and stick to the plan through month nineteen, take the avalanche and keep the savings. The math has no counterargument.
The case for the snowball
Except debt payoff is not a spreadsheet contest. It is a multi-year behavior under stress. The failure mode is not picking the suboptimal order. It is quitting.
The snowball is built against quitting. Kill a $400 balance in month one and something real happens: one fewer statement, one fewer minimum, visible proof the plan works. Each closed account frees its minimum payment, so the amount hitting your target grows like, well, a snowball. The CFPB’s own write-up is candid about the trade: the snowball may cost more in interest, and it delivers the quick wins that keep people moving. Behavioral research on debt repayment points the same direction: people who concentrate fire and close accounts early are more likely to persist.
So here is the honest verdict, and it is a Your call with a lean. If your rates sit within a few points of each other, the methods cost nearly the same. Pick snowball and enjoy the momentum. If one debt’s rate towers over the rest, the avalanche’s savings get too big to ignore, so at minimum put that monster at the front of an otherwise-snowball line. If you have abandoned payoff plans before, that is data about you, not a character flaw: choose the snowball. The optimal plan you quit costs more than the suboptimal plan you finish.
Shrink the fight before you pick the order
One move outranks both methods: cutting the rates themselves. Payoff order only divides up interest you have agreed to pay. A consolidation loan renegotiates it. Roll balances charging 25% into a loan charging 13% and you have done more for your timeline than any targeting scheme can, because every dollar now buys nearly twice the principal reduction.
So run the sequence: list every debt with its rate, check what consolidation rate your credit qualifies for, and compare consolidation loan offers against your current blended rate. If the new rate clears the bar, consolidate the expensive debts and snowball or avalanche the rest. If it does not, pick your method tonight, automate the extra payment tomorrow, and let the rollover do the compounding.
Either method beats minimum payments by years, and the rollover mechanic does the speeding up for you. The only wrong choice is spending another month choosing.