Tutorials
- How to Build an Accounts Receivable Aging Report in Excel or Google Sheets
Days overdue, aging buckets (Current, 1-30, 31-60, 61-90, 90+) and a per-client aging summary, using three formulas.
- How to Back Up n8n Properly: Database, Encryption Key and a Restore Test
Exporting workflows isn't a backup. What an n8n backup must contain, the exact commands (tested on n8n 2.40.6 with Postgres), and how to prove it restores.
- Cap Rate vs. Cash-on-Cash vs. DSCR: A Worked Rental Example
The three numbers that decide whether a rental is a deal, calculated step by step on one real-looking property, with a free calculator.
- Freelancer Taxes: A Simple Set-Aside Method and the 2026 Quarterly Due Dates
How much to move to a tax savings account each month, how the IRS estimated-tax periods really work (they are not calendar quarters), and a spreadsheet to track it.
- How to log business miles for Schedule C (2026 IRS rates)
Keep an IRS-ready mileage log for self-employed Schedule C Line 9, with the 2026 mid-year rate change from 72.5¢ to 76¢ on July 1.
- Lease Renewal Tracker Spreadsheet: Lease Expiration Alerts, Notice Deadlines and Rent Increases (Excel & Google Sheets)
Build a landlord spreadsheet that flags leases expiring in 30, 60 and 90 days, works out the last day to send a renewal or rent-increase notice, and calculates each proposed rent bump. Exact formulas, tested by recalculating a sample workbook.
- n8n Error Alerts That Don't Spam You: Error Trigger + Dedupe (n8n 2.x)
Set up one error workflow that alerts Slack, Discord, Telegram or email whenever any workflow fails, groups repeated errors, and actually fires in n8n 2.x.
- Polite Overdue Invoice Reminders: A 3-Stage Sequence That Gets Paid
Copy, timing, and a days-overdue formula for friendly, firm, and final invoice follow-ups — plus how to automate them without spamming clients.
- Rent Late Fee Calculator Spreadsheet: Grace Period, Flat + Daily Fees and a Cap (Excel & Google Sheets)
Build a rent ledger that works out days late, the late fee (flat, percent of rent, daily, with a maximum) and the balance for every charge, and flags LATE automatically. Exact formulas, tested by recalculating a sample workbook, plus how to set the grace period to match state rules like Colorado, New York and Texas.
- Build a Rent Roll That Flags Late Rent Automatically (Plus a Deposit Ledger)
Spreadsheet formulas for a rent roll that shows Paid, Partial, Due and LATE for each unit, and a security deposit ledger that always balances.
- How to Track Rental Income and Expenses by Schedule E Line (Free Spreadsheet Method)
A simple spreadsheet setup that sorts every rental transaction into its Schedule E line automatically, with the exact SUMIFS formulas.
- Rental Property Cash Flow Spreadsheet: Monthly NOI and Cash Flow per Property (Excel & Google Sheets)
Build a landlord spreadsheet that shows income, operating expenses, NOI and cash flow for each rental by month, with the exact SUMIFS formulas. Tested in Excel-compatible LibreOffice and Google Sheets syntax.
- Self-Host n8n with Docker Compose, PostgreSQL and Automatic HTTPS (2026 Guide)
A production-grade n8n 2.x setup on one small server, with Postgres 17, Caddy for HTTPS, a pinned version, and the three settings that trip people up in n8n 2.x.
- Short-Term Rental Calculator Spreadsheet: Airbnb Cash Flow, Break-Even Occupancy and Nightly Rate (Excel & Google Sheets)
Build an Airbnb/VRBO deal analyzer that works out gross revenue, NOI, cash flow after the mortgage, cash-on-cash, cap rate, DSCR, RevPAR, and the occupancy and nightly rate you need to break even. Exact formulas, tested by recalculating a sample workbook in LibreOffice and checking it against an independent model.
- How to Update Self-Hosted n8n in Docker Compose Without Losing Data (Tested 2.40 → 2.41)
The safe way to upgrade a self-hosted n8n: pin the version, back up the database and encryption key, pull, verify, and roll back properly. Every step tested in a real upgrade drill.