Two proven strategies exist for paying off multiple debts. The debt avalanche eliminates the highest-interest debt first. The debt snowball eliminates the smallest balance first. Both reach the same destination — a life without debt — but via different routes. Choosing between them is partly mathematics, partly psychology.
The Debt Avalanche: Optimised for Total Cost
List all debts ranked by interest rate, highest first. Make minimum payments on every debt. Direct every available extra dollar toward the highest-rate debt until it's paid in full. Then cascade that payment — minimum plus extra — to the next highest-rate debt. Each debt you eliminate frees up more cash to attack the next one.
With $300/month extra: the avalanche saves approximately $2,000–$3,000 in total interest compared to the snowball on this exact debt set, and eliminates the debt 4–6 months faster.
The avalanche is mathematically optimal — it minimises total interest paid across all debts. If you are disciplined and motivated primarily by seeing the math work in your favour, this is the right method.
The Debt Snowball: Optimised for Momentum
List all debts ranked by balance, smallest first. Make minimum payments on all of them. Direct extra money to the smallest balance. When it is paid off, roll that entire payment to the next smallest. The psychological reward of fully eliminating a debt keeps motivation high and prevents abandonment.
Research confirms that behaviour matters more than optimisation for most people. A slightly more expensive plan that you actually stick to beats a mathematically perfect plan you abandon after six months. If you've started and stopped debt payoff before, snowball gives you early wins that reset the motivation cycle.
How to Choose
If your interest rates are fairly similar — say, all between 5–10% — the total cost difference between methods is small. Choose snowball for the motivational benefit. If you have one dramatically high-rate debt (a 25% credit card alongside 5% student loans), the avalanche saves enough money to matter — and that large rate differential is itself motivating.
The Hybrid Approach
Pay minimums on everything. Direct a small extra payment to your one smallest debt to eliminate it quickly for the psychological win. Direct the bulk of your extra payments to your highest-rate debt simultaneously. You get the quick win of the snowball and the interest savings of the avalanche — the best of both.
The Prerequisite for Either Method
Neither strategy works if you continue accumulating new debt simultaneously. A temporary spending restriction — no new credit card charges, a strict monthly budget — combined with automated extra debt payments is the minimum viable plan. The strategies only work on a closed, shrinking debt set.