Debt Snowball & Avalanche Dual-Method Tracker

This spreadsheet runs your debts through both popular payoff methods at once: snowball, which clears your smallest balance first for quick wins, and avalanche, which clears your highest interest rate first to pay the least interest overall. Enter your debts once and see, for each method, your debt-free date, the order to pay them in, the total interest, and exactly how much the avalanche method would save.

The feature many debt spreadsheets get wrong is the rollover: when a debt hits £0, the money that was going towards it should jump straight onto the next target debt. This one is engineered to do that automatically, and you can watch it happen month by month on the schedule. The seven tabs include:

• Your Debts, holding up to 10 debts with balance, APR and minimum payment (with a warning if your budget doesn't cover your minimums)
• Snowball Plan and Avalanche Plan, each with a dashboard and a full month-by-month schedule
• Compare, putting both methods side by side with the interest saved
• How It Works & Sources, explaining the method and pointing to free debt help

The engine was checked against an independent calculation with a full worked example — 4 debts, a fixed £300 monthly budget, cleared in 17 months — covering every monthly balance, interest figure and payoff date for both methods: 4,299 automated checks, all passing.

This is a self-directed planning tool, not financial advice, and makes no guaranteed outcome. It works in any currency and opens in both Excel and Google Sheets.