Debt Snowball vs Avalanche: A Spreadsheet Comparison With Real Numbers
Short answer: the avalanche (highest interest rate first) always costs the same or less interest. The snowball (smallest balance first) gives you quicker wins. How much the choice matters depends almost entirely on your mix of debts, and a spreadsheet can tell you in a few minutes.
How each method works
Both methods start the same way: you pay the minimum on every debt, and you decide on one fixed monthly total you can put toward debt. Anything above the minimums is your extra payment. The only difference is where the extra goes.
- Snowball: put the extra on the debt with the smallest balance. When it is gone, its whole payment rolls onto the next-smallest balance.
- Avalanche: put the extra on the debt with the highest interest rate (APR). When it is gone, its payment rolls onto the next-highest rate.
The rolling part is what makes both work. Your total monthly payment never drops when a debt is paid off, so each later debt gets hit harder.
Example 1: a typical mix (the gap is small)
Four debts, a total monthly budget of $700 ($500 in minimums plus $200 extra). Interest is estimated monthly as balance × APR ÷ 12.
| Debt | Balance | APR | Minimum |
|---|---|---|---|
| Store card | $1,200 | 24.99% | $40 |
| Car loan | $8,500 | 6.9% | $260 |
| Personal loan | $4,800 | 13.5% | $150 |
| Medical bill payment plan | $600 | 0% | $50 |
| Snowball | Avalanche | |
|---|---|---|
| Payoff order (month paid off) | Medical bill (3), store card (7), personal loan (17), car loan (24) | Store card (6), medical bill (12), personal loan (17), car loan (24) |
| Debt-free in | 24 months | 24 months |
| Total interest | $1,485.49 | $1,424.10 |
The avalanche saves $61.39 over two years, and both finish in the same month. Meanwhile the snowball clears its first debt in month 3 instead of month 6. For a lot of people, an early win that keeps them going is worth $61.
Example 2: one big, expensive balance (the gap is large)
Now three debts with a total monthly budget of $645 ($495 in minimums plus $150 extra):
| Debt | Balance | APR | Minimum |
|---|---|---|---|
| Small store card | $500 | 9.9% | $25 |
| Big card balance | $9,000 | 26.99% | $270 |
| Car loan | $6,000 | 5.9% | $200 |
| Snowball | Avalanche | |
|---|---|---|
| Debt-free in | 32 months | 31 months |
| Total interest | $5,017.30 | $3,956.06 |
Here the avalanche saves $1,061.24 and a month. The snowball spends nearly two years paying down the cheap car loan while the 26.99% balance keeps growing interest. When your largest balance also has your highest rate, the avalanche is usually worth the slower start.
Build the comparison in your own spreadsheet
You can do this in Google Sheets or Excel with a few columns. A minimal version:
- A list of debts with columns for name, balance, APR and minimum payment. Add one cell for your total monthly debt budget.
- Two sort orders. Snowball rank = rank by balance, smallest first. Avalanche rank = rank by APR, highest first. In Sheets or Excel:
=RANK(B2,$B$2:$B$5,1)for balance (ascending) and=RANK(C2,$C$2:$C$5,0)for APR (descending). - A month-by-month table for each plan. For each month and debt: interest =
previous balance × APR / 12; payment = minimum, plus whatever is left of the budget if this is the current target debt; new balance = previous balance + interest − payment, never below zero. - Totals. Sum the interest column for each plan, and find the first month where every balance is zero.
Step 3 is where homemade sheets usually break: the "whatever is left" logic has to roll a finished debt's payment onto the next target, and handle the month where a debt finishes partway. If you'd rather not build that part, our Debt Snowball & Avalanche Planner runs both plans side by side for up to 10 debts and 30 years and shows your debt-free date for each.
Mistakes that skew the numbers
- A minimum payment that doesn't cover the interest. If balance × APR ÷ 12 is bigger than the minimum, that debt grows while it waits its turn. Check this first.
- Ignoring promotional 0% periods. A 0% balance that jumps to a high rate in eight months should usually be treated as high-rate now.
- Still adding new charges. Neither method works if a balance you are paying down keeps growing. Pause the card while you pay it off.
- Letting the total payment shrink. When a debt is gone, keep paying the same monthly total. That rollover is the whole engine.
- Expecting lender-exact figures. Lenders compute interest daily and on their own schedule, so a monthly estimate will drift by a few dollars. It is close enough to compare methods.
So which should you pick?
Run both. If the avalanche saves only a small amount, pick whichever you'll actually stick with; many people choose the snowball for the early momentum. If the avalanche saves hundreds or thousands, it is hard to argue with. A hybrid works too: clear one tiny balance first for the quick win, then switch to avalanche order.
This guide is general education, not financial advice. Figures were calculated with a monthly-interest model (balance × APR ÷ 12) and rounded to the cent.