Debt & Credit
The avalanche and snowball methods, and when each is right
One pays less interest, the other is finished more often. The evidence on which works is not what the arithmetic suggests.
Everything below about debt repayment strategies comes from what actually happens rather than from what is supposed to.
What holds up in practice
- Avalanche — highest rate first — always costs less in interest.
- Snowball — smallest balance first — has better completion rates in studies.
- Both beat paying minimums across everything, by a wide margin.
The two methods in one paragraph
Both approaches pay the minimum on every debt and direct all spare money at one target. The avalanche targets the highest interest rate first, which minimises total interest paid.
The snowball targets the smallest balance first, which clears individual debts faster and reduces the number of creditors. The difference in total cost between them is usually smaller than people expect, unless one debt has a dramatically higher rate.
The arithmetic favours avalanche
Interest accrues on balances at their own rates, so attacking the most expensive one first mathematically minimises the total paid. Where one debt carries a rate far above the others — a payday loan, an overdraft, a store card — the case is overwhelming.
Nobody disputes this part; the disagreement is about whether people follow through. The ranking needs the rate actually being charged rather than the one advertised, since arrangement fees, daily compounding and charges applied per transaction can make a nominally lower rate the more expensive debt.
The evidence favours snowball for completion
Research on consumer debt repayment has repeatedly found that people using the smallest-balance-first approach are more likely to finish. The mechanism appears to be motivational: closing an account produces visible progress that a falling balance does not.
A method that is completed beats a cheaper method that is abandoned, which is the practical case for snowball. Much of that work rests on observational data and on experiments with modest sums, so it describes a tendency rather than a law, and the tendency is unlikely to hold against a debt whose rate outruns the progress you can see.
A hybrid usually beats either
Clearing one or two small balances first for momentum, then switching to strict highest-rate order, captures most of both effects. Any debt at a genuinely punitive rate should jump the queue regardless of balance.
The order matters far less than the amount you direct at it, which is the variable most people ignore. The engine underneath both methods is the same: every cleared debt frees its minimum payment, and rolling that freed amount onto the next target rather than back into spending is what makes the final debts fall so much faster than the first.
What matters more than the method
Stopping new borrowing is the precondition; no repayment strategy works alongside continued accumulation. Reducing the interest rate through a balance transfer or consolidation can save more than any ordering decision, if the fees are checked. Where debts are unaffordable rather than merely large, free debt advice services exist in most countries and are a better first call than any strategy.
Consolidation that reduces the monthly payment by extending the term frequently raises the total interest paid, so the number worth comparing is the total cost to clear rather than the payment.
Rates, thresholds and rules differ by country and change often — check current figures before acting.
Some debts jump the queue whatever their rate
A promotional zero-rate balance with an end date behaves like a deadline rather than a rate, so clearing it before the standard rate applies can outrank the ordering rule entirely. Where a lender charges interest on the full original balance if the promotional period is missed, being a month late costs far more than the headline rate suggests. Debts secured on your home or your vehicle carry a consequence for non-payment that no interest calculation captures, which is why arrears there are dealt with before any optimisation begins.
In numbers, which arrears count as priority is set by national law rather than by arithmetic, so the local order is worth confirming before spare money goes to the wrong creditor.
The takeaway
Pick whichever one you will actually finish, and put more money at it than feels comfortable.
Costs compound as reliably as returns do, and in the same direction.
Questions readers ask
Should I save or pay off debt first?
Keep a small buffer so ordinary surprises do not go back on the card, then prioritise debt costing more than you could earn on savings.
Do balance transfers hurt your credit file?
Applying creates a temporary mark and opens a new account, but reducing utilisation usually helps over time. Check the transfer fee against the interest saved.
