I cancelled my Copilot subscription and switched to Claude for Office tasks

If you use Microsoft 365 apps and need some AI assistance, Microsoft Copilot is an obvious choice. It's tightly integrated into Microsoft apps and into Windows itself if you use a PC, and it works quite well out of the box. However, I also use Claude, which I think is superior to anything Copilot has to offer.

So, just as Anthropic released its official add-ins for Microsoft 365 apps, I dialed down my Microsoft 365 subscription to the Personal plan and switched to Claude for Office tasks, and I've only been more and more impressed by Claude and its Opus 4.8 model.

Setting up Claude for Office apps

A paid plan and one add-in cover everything

To get started, you need to meet a few requirements. First, Claude for Office is only available for paid users, which is anyone on the Claude Pro, Max, Team, or Enterprise plan. The free tier won't work, so factor that into the math if you're weighing it against Copilot.

You also need a Microsoft 365 subscription with desktop versions of Word, Excel, and PowerPoint (2016 or later) on Windows or Mac. The add-in works in the web versions of these apps as well, so even the browser-only crowd is covered.

Find the Claude for Microsoft 365 listing on the Microsoft Marketplace, click Get it now, and sign in with your Microsoft account. From the listing page, use the Open in Word, Open in Excel, and Open in PowerPoint buttons to attach the add-in to each app.

After that, a Claude icon shows up on the ribbon. Click it, sign in with your Claude account once, give any necessary permissions, and the sidebar is ready. There's also an Outlook add-in, currently in beta, if you want Claude in your inbox too. But that's beyond the scope of this article.

Asking Claude to edit my Word file

Skills turn it into a proper copy editor

I mainly use Word to write and edit my articles, and the built-in spelling and grammar checks miss a lot of grammar and styling issues. Copilot can proofread and copyedit, too, but it doesn't have access to the same set of Skills that Claude has. Skills are reusable instruction sets that teach Claude how to do a specific job the same way every time.

Claude for Word ships with a /copy-edit skill, so instead of writing a prompt, I typed /copy-edit and hit Enter. It scanned the document for a few seconds, offered seven corrections and one style consistency issue, and applied the fixes across all 27 paragraphs automatically. Edits land as tracked changes, so nothing slips in without my knowledge.

Then I gave it a more precise instruction: check each sentence in the lede for phrasing issues, awkward word choices, or incorrect conjunctions. It came back with a handful of suggestions on how to improve the lede, each with a short reason attached.

Another use case for writers is fact-checking. I asked Claude to check the article for factual inaccuracies and outdated information. It ran a few web searches, confirmed most claims were accurate, and correctly flagged the one that needed attention. Word's built-in editor was never going to do that.

Claude can help you with your Excel sheet

It writes the formulas, and Excel does the math

You'd think a language model would be a liability around numbers, but Claude doesn't do the arithmetic itself. It writes the formulas, and Excel does the math, which sidesteps the usual AI math problem entirely. The add-in handles a variety of tasks and is, honestly, miles ahead of anything I've seen inside Excel, and it's good at self-auditing.

It can help you quickly understand the structure of other people's workbooks. Point it at an inherited file, and it reads every tab, cell, and formula, then explains how the sheets connect in plain English. Ask it about a specific formula, and it breaks down constructs like INDEX/MATCH step by step. It also fixes common errors like REF, VALUE, and circular references while explaining what went wrong.

The self-auditing part is even more impressive. Drop a vendor's PDF statement into the sidebar, and Claude parses the line items into a sheet, then cross-checks the rows against the subtotals and tax values in the PDF before declaring the job done. I've seen Claude in action before, back when I gave Claude broken data, and it turned it into a usable spreadsheet, and the Excel add-in carries that same habit of checking its own work.

Claude has an eye for slides, too

Template-aware edits, not generic makeovers

Claude also works with PowerPoint, so if you are planning to create a presentation slide out of your Excel data, the add-ins can share context. With both apps open, I can ask Claude to build an executive summary slide from the Excel analysis it just finished, and it pulls the figures across without any copy-paste on my part.

What separates it from a generic AI slide generator is template awareness. Claude reads the slide master, layouts, fonts, and color scheme before touching anything, so new slides match the deck instead of looking bolted on. It can generate a full presentation from a single prompt, and the structure it picks is sensible rather than padded.

It's just as useful on existing decks. I've had it cut a six-bullet summary slide down to three clear takeaways, merge two overlapping slides into one, and convert bullet points into native, editable charts. When I asked it to improve a dull deck, it first asked whether I wanted a light, medium, or heavy makeover and requested approval before applying changes.

Not a flawless switch, but one I'd make again

The Claude add-ins for Microsoft Office have their quirks. The permission prompts, for instance, while sensible, make it slower than Copilot's instant suggestions; the chat doesn't persist once you close the file, and you're paying for a Claude plan on top of Microsoft 365. Copilot also remains better woven into Windows itself, and everything Claude produces still needs a human read before it ships.

But the work I do in these apps is writing, editing, and the occasional spreadsheet, and Claude is simply better at all three. And it's only going to get better.