Copilot in Word and Excel: what Microsoft documents it does — and doesn't

Copilot in Word and Excel — part of Microsoft 365 Copilot, per Microsoft's product and licensing documentation — provides drafting from prompts and company context in Word, rewriting and tone adjustment on selections, document and thread summarization, and in Excel natural-language questions over tables plus formula help, with Microsoft's commercial terms stating that customer content is not used to train the models. The documented shape is assistance inside the file you're editing rather than a separate destination: outputs arrive as drafts to accept, edit, or reject, which builds the review step into the interface — the property that makes embedded assistance safer than pasting into external tools, and easier to skip when deadlines press.

RechargeMe publishes information, not advice, and no testing. Everything below follows Microsoft's published documentation as of early 2026; licensing tiers and feature availability vary by plan and region.

What do the Word features document?

Drafting: a prompt produces a full document draft or section, optionally grounded in a referenced file — Microsoft documents the ability to base drafts on other documents in your workspace, the feature that most distinguishes embedded Copilot from a generic chatbot. Rewriting: selected text re-generated in a specified tone, length, or format — the fastest everyday use. Summarization: long documents condensed, and in the email context Copilot summarizes threads, per the Outlook documentation. And reference Q&A: questions answered about the document open in front of you, with the honest limit that summarization and Q&A inherit the document's own errors — a wrong number in the draft is a wrong number in the summary.

What do the Excel features document?

The spreadsheet side, per Microsoft's pages: natural-language analysis suggestions over formatted tables — trends, outliers, visualizations proposed from the data; formula assistance — describe the calculation, receive the formula, the same documented pattern covered in this series' formula guide with the same verification duty; and data transformation help. The documented constraint worth knowing: Copilot's Excel features work best on well-formatted tables — clean headers, consistent types — and degrade on messy sheets, which is the AI-flavored version of Excel's eternal rule that garbage layouts produce garbage analysis, now produced faster.

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What about privacy and grounding?

The documented enterprise posture: Microsoft's commercial terms state that customer data is not used to train the underlying models, and Copilot's grounding respects the user's existing permissions — it surfaces content you already have access to, per Microsoft's Copilot privacy documentation, which is the load-bearing design point in organizational settings: Copilot doesn't leak what you couldn't see; it also doesn't hide what you could, a subtlety IT departments discover when search surfaces documents nobody remembered were shared broadly. For individuals on personal plans, different consumer terms govern; for organizations, admin controls gate availability per Microsoft 365 licensing. The rule this series keeps repeating applies one more time: which side of the commercial-consumer line your plan sits on determines the data terms — verify for your exact tenant.

What is it genuinely good at?

Documented strengths, matched to real desk work: first drafts of routine documents — meeting recaps, project briefs, status sections — where the empty page costs more than the polish; the ruthless edit — tightening a flabby section while preserving meaning, the rewrite feature's sweet spot; and thread archaeology — summarizing the forty-reply email chain before the meeting, the Outlook-side feature that pairs naturally with Word drafting. The Excel analysis suggestions are best treated as a junior analyst's observations: occasionally insightful, worth checking, never authoritative — the documented behavior is proposal, not finding.

What are the limits the docs admit — and the ones they don't?

Admitted: availability by plan; grounding limited to content you can access; output quality dependent on input clarity — Microsoft's own prompt guidance leans heavily on providing context and examples. Unadmitted but documented by the general behavior of the underlying models: fluency that reads as accuracy — the Copilot draft of a report states its wrong number as confidently as its right ones; grounding failures where the draft cites a source file's content loosely; and the review-skipping risk that embedded convenience creates — accepting a rewrite without reading the diff is the Office equivalent of shipping unreviewed code, with the compliance version of that risk being a report that confidently misstates a fact upward. The review habit is the product; the features just accelerate both halves.

FAQ

• Does Copilot in Office train on my documents? Microsoft's commercial terms state customer content is not used to train the models; consumer plans are governed by different terms. Verify for your exact plan and tenant.
• What does Copilot do in Excel? Natural-language analysis suggestions over formatted tables, formula help, and transformation assistance, per Microsoft's documentation — best on clean tables, always with verification of formulas and assumptions.
• Is Copilot's Word drafting grounded in my files? It can be — Microsoft documents drafting based on referenced documents within your access permissions, which is the feature distinguishing it from generic chat, and the reason to check drafts against those sources.