Debt Avalanche Spreadsheet That Saves Real Interest

Hey folks, it's Ren here.

I walked a small section of a coastal track last weekend. Nothing brutal, just enough elevation that the calves had something to say about it on the way back down. About halfway up there is a sign that gives you two routes to the lookout, a short steep climb that gets you there faster and a longer switchback that costs less effort per step. Same destination. Different cost.

Debt payoff strategies work the same way. The snowball climbs by smallest balance, easier early steps and a sense of momentum. The avalanche climbs by highest interest rate, harder first step and lower total cost. Different routes to the same lookout.

A debt avalanche spreadsheet is the route map for the cheaper climb. It orders every debt by interest rate, applies your extra repayment to the most expensive one until it is gone, then rolls the freed-up payment onto the next. Less paid in interest, fewer months in debt, more money kept.

"Compound interest is the eighth wonder of the world. He who understands it, earns it; he who does not, pays it." — Albert Einstein

📊 What the debt avalanche actually is

Three steps, no more.

List every non-mortgage debt with the current balance, the interest rate, and the minimum payment. Sort the list by interest rate, highest at the top. Pay the minimum on everything; throw every spare dollar at the top of the list. When the top debt is gone, take its old minimum plus the extra and add it to the next one down. Repeat until the list is empty.

That is the whole method. The spreadsheet exists to keep the order honest as balances change, to show the projected payoff date so the climb feels finite, and to track the cumulative interest saved versus paying minimums alone. None of those numbers are exciting on day one. By month four they start to be.

💰 When avalanche actually beats snowball (the bit most posts skip)

Here is the differentiator. Almost every comparison post tells you avalanche saves more interest. True, on paper. The honest answer has a condition attached.

Avalanche beats snowball in cost, and the gap matters most when the interest rate spread between your debts is wide. A credit card at 22 percent next to a car loan at 7 percent is the textbook avalanche case. Paying the card down first saves real money that the snowball method gives away.

Avalanche stops mattering, and snowball becomes the better answer in practice, when the rate spread is narrow (everything sits within a couple of percentage points) or when the highest-rate debt has a much bigger balance than everything else. In that second case the climb to the first paid-off debt is long. Long climbs without a checkpoint are where debt plans quietly die.

So the practical rule is: if your top-rate debt is meaningfully more expensive than the next one (say four percentage points or more) and its balance is not three times bigger than the next one, run avalanche. Otherwise the motivation cost of snowball is usually worth the small extra interest. If you want to see the snowball view side by side before you decide, our free debt snowball calculator models the smallest-balance path against your real numbers.

Please do not be hard on yourself if you have started with one method and want to switch. The plan that runs is always better than the plan that is theoretically optimal.

📋 What goes in a debt avalanche spreadsheet

Six columns. That is the whole sheet.

Debt name. Be specific. "Westpac Visa" beats "credit card" when there are three of them. Current balance, as of today. Interest rate, the actual annual rate from the statement, not the marketing rate. Minimum monthly payment, from the statement. Extra payment, the spare dollars you are adding from the budget. Projected payoff month, calculated from the other five.

A small panel at the top of the sheet shows the rolling total: total balance remaining, total minimums per month, total extra, projected total payoff date, total interest saved versus paying only minimums. The panel is the dashboard. Look at it once a fortnight.

🛠️ How to set up a debt avalanche spreadsheet

About forty-five minutes, including pulling the statements.

1. Gather every statement. Credit cards, personal loans, car loan, BNPL accounts, family loans you have written down. Anything with interest or a regular payment.
2. Enter each as a row. Name, current balance, interest rate, minimum payment. Triple-check the interest rates against the most recent statement, not the original contract.
3. Sort by interest rate descending. Highest at the top, lowest at the bottom. Mortgage is normally left out of an avalanche sheet because it sits in a different time horizon.
4. Set your extra payment line. The spare amount you can add every month, on top of the minimums, without breaking the rest of the budget. Conservative beats heroic; a tight extra you actually pay beats a generous extra you cannot sustain.
5. Direct the entire extra to row one. Everything else gets minimums only. The temptation to spread the extra evenly is what turns avalanche into a slower, less powerful version of itself.
6. When a row hits zero, roll its payment up. Add the cleared row's old minimum to the extra and apply the full new amount to the next row down. Do not pocket the freed-up payment. The roll-up is the whole engine.

If the wider context of debt strategy and tradeoffs is what you actually need, the pay off debt guide walks through the methods, the order, and how to choose between them.

⚠️ Mistakes to sidestep

• Spreading the extra payment across all debts. Fix it: full extra to the top row, minimums on everything else. Spreading is snowball without the motivation, avalanche without the savings.
• Using the contract rate instead of the current statement rate. Fix it: pull the latest statement for each debt; promotional rates and rate jumps change the order of the list.
• Pocketing the freed-up minimum after a debt clears. Fix it: roll the old minimum into the extra and direct the new total to the next row. The roll-up is where the months really start to fall.
• Adding new debt while paying the old debt down. Fix it: pair the avalanche sheet with a written rule that no new credit is opened until the list is shorter than it is today. The plan cannot outrun the inflow.

🎯 Your action steps this week

• Pull every non-mortgage statement and write down name, balance, interest rate, minimum payment.
• Sort the list by interest rate, highest at the top.
• Decide the extra payment from the budget. Be honest about what is sustainable.
• Apply the entire extra to the top row, minimums on the rest, for the next three months without changing the order.
• If snowball motivation looks more important for your situation, run the numbers through our debt snowball calculator first and compare the projected payoff dates side by side before committing.

❓ Frequently asked questions

Scenario 1: I have three credit cards at 18 to 22 percent and a car loan at 7 percent. Which method?

Avalanche, and it is not close. The spread between the cards and the car loan is wide, the cards are the expensive climb, and clearing them first will save real interest. Order the three cards by their current rate, highest first, and direct the full extra to the top card until it clears. The car loan stays on minimums for now.

Scenario 2: I have one big personal loan and three small BNPL balances. Which method?

Snowball is usually the better answer here. The small BNPL balances will clear in weeks, the freed-up payments roll into the personal loan, and the wins keep the plan alive while the loan grinds down. The total interest difference is small because BNPL rates are usually low or zero; the motivation difference is large.

Scenario 3: I have a mix of cards, a HECS or student loan, and a small medical bill. Which method?

Run avalanche on the cards alone first, because the rates are the highest by a wide margin. Pay the HECS or student loan on its standard schedule (its rate is usually tied to indexation and behaves differently). Clear the small medical bill quickly from the buffer if you can, because medical debts often have collection consequences that cost more than the interest does.

Halfway down the track on the way back, the short steep route looked different on tired legs than it had on fresh ones. The avalanche works the same way: the early weeks are harder than the snowball weeks, the late weeks are easier, and the total cost of the climb is lower. The spreadsheet keeps the order honest while the legs do the work.

To your financial freedom,
Ren

This article is for general information only and is not financial advice. It does not take into account your personal situation, needs or objectives. Please consider speaking with a qualified financial adviser before making financial decisions.