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Find out the month and year you'll be debt-free and which payoff method saves you the most.

• Up to 10 debts: credit cards, personal loans, car loans, student loans, medical bills, and installment plans

• True APR for fee-based installment plans (store financing, card installment plans, longer-term BNPL financing): enter the flat fee and number of installments, and the sheet converts it to a real APR. A "small" 1.5% monthly fee on a 6-month plan works out to 30.23% APR (34.79% effective). Scheduled fees are counted in full even if you pay early, as most plans charge them. Standard Pay-in-4 plans (Afterpay, Klarna) are usually 0% interest, so enter those at 0% APR. Avalanche puts fixed-fee plans last, because paying them early saves nothing.

• Snowball vs Avalanche, side by side: see the payoff month and date (month/year) and the interest & fees for each debt, the total interest & fees for each method, and how much you save

• Extra-payment input: change one number and watch your debt-free date (month/year) move. Set your start month and every payoff shows as a real date

• Month-by-month schedule for up to 120 months, with payments rolling over automatically when a debt is paid off

• Chart of your total balance over time

• Warnings: any debt the plan can't clear within 120 months is flagged on the Debts tab, the verdict says so plainly, and interest totals are marked as covering the first 120 months only. A softer note shows when a minimum payment alone doesn't cover the interest.

• Input checks: out-of-range inputs (APR above 100%, balance above 1,000,000) are flagged in the Warning column and capped in the calculations.

• Editable currency symbol, so it works in $, £, €, or any other currency

Works in Google Sheets (File → Import) and LibreOffice, both tested; Excel 2010+ should work but has not been tested yet. No macros.

Estimates only, not financial advice. Original work, licensed for personal use only.