Try SheetBrain on a synthetic workbook with 5 planted issues
No need to bring your own messy spreadsheet. Copy the demo into your Drive, install SheetBrain, and run Check — you'll see examples of the issues SheetBrain looks for, all in under two minutes.
Make a copy of the demo workbook
Opens a "Copy document" dialog in Google Sheets. The workbook lands in your Drive as a private file you can edit.
Make a copy →The workbook is fully synthetic — placeholder customers (Acme, Beta), placeholder regions (North, South), and made-up numbers. Nothing from anyone's real spreadsheet.
Install SheetBrain
Free install from the Google Workspace Marketplace. Works with any Google account, including free Gmail.
Install SheetBrain →Open the sidebar and run Check
In your copy of the workbook, open Extensions → SheetBrain → Open sidebar. The sidebar lands on the Health tab. Click Scan sheet on each of the five issue sheets (Lookups, Sales totals, Customers, Margins, Forecast) to see what SheetBrain flags.
Sheet Check scans are free and unlimited — no AI call, no quota hit.
What you should see
Each sheet has exactly one planted issue. Here's what SheetBrain flags on each, with a short note on why.
| Sheet | Cell | Severity | What SheetBrain says, and why |
|---|---|---|---|
| Lookups | C2 |
Error | Broken reference. The VLOOKUP asks for column 3 of a 2-column range. SheetBrain spots the out-of-range index and proposes a clamped fix for you to review. |
| Sales totals | B7 |
Warning | Mixed text and numbers. The Amount column is mostly numeric, but row 7 holds the text "TBD". SUMIFS would silently undercount. |
| Customers | C2 |
Warning | Duplicate lookup keys. The VLOOKUP for "Acme" targets a column where "Acme" appears twice. VLOOKUP silently returns only the first match. |
| Margins | C5 |
Warning | Missing copied formula. Rows above and below all use =B−A, but row 5 has no formula. Easy to miss visually. |
| Forecast | B2 |
Error | Visible formula error. The VLOOKUP for "Mango" has no match in the key column, so the cell shows #N/A. |
Want the full catalog of what SheetBrain checks for? Read the v0.4 detector set spec.