The Ultimate Guide to Debt Payoff Strategies (Snowball vs Avalanche)

The avalanche method (extra money goes to the highest interest rate first) costs the least interest, and the snowball method (extra money goes to the smallest balance first) clears accounts sooner at a higher interest cost. In the example below, three debts totalling $12,700 are paid off with a fixed $645 a month. Avalanche finishes in 24 months with $2,419.15 of interest. Snowball finishes in 25 months with $3,015.93. The avalanche saves $596.78 and one month.

The Example and Its Assumptions

• Total monthly budget: $645, which is $345 in minimums plus $300 extra.
• Interest accrues monthly at APR divided by 12 on the balance, rounded to the cent, and each payment is made after interest is added.
• APRs stay fixed, nothing new is charged, and there are no fees or promotional rates.
• When a debt is paid off, its minimum payment is added to the next target, so the total paid each month stays at the full budget until the last debt is gone.

The Two Orders

Snowball order is by balance: Store card, then Personal loan, then Credit card. Avalanche order is by rate: Credit card, then Store card, then Personal loan. The $7,200 credit card is last under snowball and first under avalanche, and it carries the highest rate, which is why the two methods diverge here.

Month-by-Month Results

Snowball gives you a win in month 5, 14 months before avalanche clears its first account. That early win is the whole case for it. The remaining balance across all debts shows how the paths separate.

Avalanche owes less at every checkpoint because the $7,200 balance stops accruing 24% interest sooner. At month 24 avalanche owes nothing and snowball owes $231.

When the Gap Shrinks

The saving comes from the spread between rates, and from how big the high-rate balance is. Change only the rates to 19%, 20% and 18% (store card, credit card, personal loan) and both methods finish in 24 months, with $2,733.95 of interest for snowball and $2,641.35 for avalanche. The gap falls from $596.78 to $92.60. When rates are close, choose the order you will stick to.

What Doing Nothing Costs

If each debt only gets its own minimum and nothing is added, the same debts take 81 months and cost $8,737.57 in interest. If you paid the $345 total but rolled each freed minimum forward, it takes 59 months and $7,427.42. The extra $300 a month, aimed well, is what shortens the plan to about two years.

Picking a Method

The dollar cost of choosing snowball here is $596.78 over about two years, roughly $23.87 a month. Whether that is worth early wins is a personal call, not a mathematical one, and this guide does not claim a measured completion rate for either method. A sensible compromise is to clear any tiny balance first for the quick win and then switch to highest rate first. If you are already motivated and organised, avalanche is the cheaper default.

Common Mistakes

• Adding new charges to cards you are paying off. The plan assumes balances only fall.
• Skipping minimums on non-target debts. Late fees and penalty rates can erase the saving.
• Choosing a method for its reputation instead of your own numbers. Run both.
• Ignoring promotional rates that expire. A low rate today can jump later, so recheck when terms change.
• Starting with no cushion at all. A small emergency buffer stops an unexpected bill from going back on a card, though how much is a personal judgement.

Should Extra Cash Go to Debt or Investments?

Paying off a debt is a guaranteed return equal to its interest rate: a dollar used on a 24% card avoids 24% a year in interest. An investment return is uncertain and varies, and past performance does not guarantee future results. That arithmetic favours paying down high-rate debt first; for low-rate debt the comparison is closer and depends on your goals and comfort with risk.