An AI tool can work with spreadsheet data without sending the workbook to a cloud model—but “the model runs locally” is not, by itself, proof that nothing leaves your computer. To explain a real no-upload design, its builder needs to account for every step: what the add-in reads, where inference happens, what it writes back, and which network requests remain. The available evidence explains how to assess that claim; it does not establish the architecture or testing of the specific tool named in this headline.
What “never uploads your files” needs to mean
A defensible claim starts by defining “your files.” An Excel add-in might read only a selected range, or it might access broader workbook content. It may encounter cell values, formulas, sheet names, comments, workbook structure, or metadata. Excel workbooks can retain information that is not visible in the grid, including author details, comments, tracked changes, and linked-data paths, as Microsoft explains in its Excel privacy supplement.
As an Amazon Associate I earn from qualifying purchases.
That makes “we don’t upload the workbook” less precise than readers need. The relevant questions include whether any workbook content is transmitted, whether prompts include copied cell data, and whether the tool sends diagnostics or identifiers that could reveal information. A useful disclosure names exactly what the add-in can read and what, if anything, it sends off-device.
Quick wins for a faster PC:
Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Clear out junk files and repair common Windows errorsFree Scan →Trace the data from Excel to the result
A clear build account should make the data path inspectable rather than relying on the word “local.” For each operation, describe the input, processing location, output, and network activity. For example, a trace should say whether the user selects cells, whether the add-in reads values or formulas, whether a model runs on the same computer or elsewhere, and whether generated output is inserted as a formula or a value.
#1 Best Overall
- The Microsoft Office 365 Bible: The Most Updated and Complete Guide to Excel, Word, PowerPoint, Outlook, OneNote, OneDrive, Teams, Access, and Publisher from Beginners to Advanced
- ABIS BOOK
- Workbook access: Identify the exact sheet or range the feature reads and whether it can access formulas, comments, structure, or metadata.
- Prompt construction: Explain whether selected content is added to a prompt, transformed, or stored locally.
- Inference: State where the model runs: on the device, on a local network, or through a remote service.
- Result handling: Say where responses appear and whether formulas recalculate or results remain static.
- Network requests: Account for model downloads, update checks, telemetry, licensing, and any external API calls—not only requests made during inference.
Without those project-specific details, the headline’s claim cannot be independently evaluated. The available sources do not establish which cells the named tool reads, which model or runtime it uses, what permissions it requests, or what tests were performed to verify its network behavior.
Why a local model is not the whole privacy story
Microsoft says Office Add-ins run in a browser control or iframe, and most can read or write the active document. Add-ins use a permissions model, and Microsoft advises developers to request only the permissions their features need. That guidance describes the platform; it is not a guarantee that every add-in handles data the same way. See Microsoft’s Office Add-ins privacy and security documentation.
Local inference and local storage are also different claims. An app could process selected data on the computer but still download a model, check for updates, or transmit telemetry. Conversely, downloading a model does not establish that workbook content is uploaded. A credible privacy explanation separates these flows and states which ones occur.
Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Repair Windows errors before they cause bigger problems3Fix the driver behind crashes, sound loss and screen glitchesWhat a comparable local Excel add-in shows—and does not show
Microsoft Marketplace’s listing for Boardflare’s separate “Local AI” add-in says it uses WebGPU for local processing and that it downloads a model on first use. The listing also claims, “Your data never leaves your device,” and describes the formula syntax =LOCAL.AI(prompt). Those are the listing’s claims about Boardflare’s product, not evidence about the tool in this article or independent verification of either product’s data handling. The listing is at Microsoft Marketplace.
How this differs from other Excel automation
“AI in Excel” covers products with different data flows; they should not be treated as interchangeable. Microsoft says Office Scripts are stored in OneDrive by default and require internet connectivity to access them. That makes Scripts a useful contrast for automation, but it does not describe a wholly local implementation. Microsoft’s Office Scripts storage and ownership documentation was last updated July 24, 2026.
OpenAI’s documentation for ChatGPT for Excel says that product processes prompts, attachments, and relevant spreadsheet context. It also says Microsoft may be able to read workbook content, attachments, and prompts under Microsoft Marketplace terms. Those statements apply to that product and its Marketplace context, not to every cloud AI service. Details are in the ChatGPT for Excel and Google Sheets help page.
Rank #4
What to check before trusting a no-upload claim
- Does the privacy explanation specify whether the add-in reads a selected range or broader workbook content?
- Does it distinguish cell values from formulas, comments, workbook structure, and metadata?
- Is inference performed on the device, on a local network, or by a remote service?
- Are model downloads, updates, telemetry, licensing checks, and other requests disclosed separately?
- Do the add-in’s requested permissions match the features it offers?
- Does the builder describe how network activity was checked, and what that check covered?
Those questions let readers compare privacy properties rather than relying on labels such as “local” or “private.” They also expose the difference between a product’s stated policy and an independently demonstrated guarantee.
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
