Welcome to the Barn

WorkbookBarn sells spreadsheet workbooks that arrive finished — every formula written, tested and proved before the file goes on sale. This post is the front door: what is here, what is free, and how the testing works.

What is on the shelves

Forty-seven workbooks across five shelves. Trackers cover personal money: net worth, a budget built around your paycheck dates, debt payoff, the subscriptions you forgot about. Checklists & SOPs are the systems a small business is meant to have written down. For Agents is prospecting, pipeline, listing marketing and annual planning for working real-estate agents. Real Estate is the investor arithmetic: deal analysis, loan screening, reserves, 1031 timelines, equity waterfalls. Contractors is bids, margins, crew schedules and job settlements. Every one opens in free Google Sheets and in Excel. One purchase, no subscription.

What is free

Thirty-nine calculators run in your browser. Each one is generated from the same specification as the workbook it belongs to, so the two cannot drift apart. Nothing to download, no email, no account; what you type stays on your device.

How testing works

Every workbook is opened in a calculation engine, rebuilt from scratch, scanned for error cells and compared, figure by figure, against values worked out independently in code. One disagreement stops the release. Each product page shows the ledger of checks it passed — the full method is on How we test.

What to expect here

Guides arrive three times a week, each with a worked example and the calculator it uses. This blog is for the rest: what shipped, what broke in testing and got fixed, and what we learned. It is written from Richmond, Kentucky, by Marcos Gil, who uses these numbers for a living.

Start with the free calculators, or browse the collection.