Bookkeeping spreadsheet for small business owners who track money in a spreadsheet, not accounting software. Four sheets, formulas already wired, 10-minute setup. WHAT YOU GET - transactions.csv - the daily log: date, description, category, income, expense, method, invoice ID, notes. 15 sample rows show the format, delete them and start logging. - cashflow-summary.csv - monthly rollup for all 12 months of 2026 (income, expense, net, cumulative net) plus income, expense and net per category. SUMIF and SUMIFS formulas pull from the Transactions sheet as you type, with full-column references so there is no row limit. - invoices.csv - invoice tracker with issued date, due date, amount and status (draft / sent / paid / overdue). The instructions include a days-overdue formula and 30/60/90-day aging buckets so you can see which clients to chase and how loudly. - tax-prep.csv - 10 common deductible categories with examples and what records to keep, plus a quarterly estimated-payment worksheet that reads your live income and expense totals. - instructions.md - 10-minute setup for Google Sheets and Excel, every formula explained in plain language, invoice aging walkthrough, troubleshooting for the two common import problems. HOW IT WORKS Import the CSVs into Google Sheets (File > Import) or Excel (Data > From Text/CSV), name the tabs to match, done. Every summary cell is a live formula: add a transaction row and the monthly totals, category totals and quarterly estimates update themselves. The sample data spans January to March 2026 and the instructions list the exact numbers you should see after import, so you can confirm everything landed before you start. Works in Google Sheets and Excel 2007+ (a note in the instructions covers locales that need semicolons instead of commas in formulas). No subscription, no macros, plain CSV files you own. Personal and commercial use allowed; no resale of the pack as-is. DISCLAIMER This is a record-keeping tool, not tax advice. The deductible categories and 25% set-aside percentage are generic examples - confirm yours with an accountant or your tax authority.