Debt Payoff + Budget System: Spreadsheet + 90-Day Guide (Google Sheets & Excel)

Know your debt-free month, and see which payoff order costs you less.

This is the spreadsheet I'd hand a friend who wants to get out of debt with a plan instead of guesswork. You list your debts once, type what extra you can pay each month, and it builds your month-by-month payoff plan two ways, side by side:

• Snowball: smallest balance first, for quick wins.
• Avalanche: highest interest rate first, usually less interest.

You see your debt-free month, the total interest for each method, and the month each debt is paid off. Change one number (say, $50 more a month) and the whole plan updates.

What's inside

• Budget tab: plan every dollar of take-home pay, track actual spending, and see what's left in each line.
• Debts tab: up to 10 debts (cards, car loan, student loans, medical bills).
• Compare tab: snowball vs avalanche, with a chart of your total debt shrinking.
• Snowball and Avalanche tabs: exactly what to pay on each debt, every month, for up to 30 years.
• Emergency Fund tab: a starter goal and a full goal based on your real essential costs.
• A 13-page PDF guide, "Your First 90 Days": step-by-step setup, worksheets, a 90-day checklist and three month-review pages.

Works in Google Sheets and Microsoft Excel. No subscription, no bank login, no app. Your numbers stay in your own file.

How the math works

Interest is added monthly (balance × APR ÷ 12, rounded to the cent). When a debt is paid off, its payment rolls to the next one, so your total monthly payment stays the same. We tested the formulas against a separate calculation on several example plans, and they matched to the cent. Your lender may calculate interest daily or change your rate, so check your statements each month and update your balances.

Who it's for

Anyone with more than one debt who wants a clear order and a date to aim for. No spreadsheet skills needed: yellow cells are yours to fill, everything else calculates.

Honest note

This is an educational planning tool, not financial, tax or legal advice. It doesn't guarantee a payoff date or result. The example numbers inside are made up so you can see how it works.