The ChatGPT Excel Add-In: Free on Every Plan, and What It Actually Costs

OpenAI has quietly finished something it started in the spring. As of 17 September 2026, ChatGPT runs inside Microsoft Word, which means the same sidebar now lives in Word, Excel and PowerPoint, plus Google Sheets. OpenAI's own release note puts it plainly: "Word joins Excel and PowerPoint through the same Microsoft add-in." And unlike Microsoft's own Copilot, it reaches the free tier.

That is the headline everyone has run. Here is the part almost nobody has: the ChatGPT Excel add-in is free to install on every plan, but it is not free to use. Every message spends token-based usage, and on paid plans it draws from the same allowance as Codex. There is also a date worth knowing before it arrives, because on 1 October 2026 the Word sidebar switches itself on whether you asked for it or not.

The Key Takeaways

• One add-in, three apps: OpenAI confirms Word, Excel and PowerPoint all run from a single Microsoft add-in. You do not install three things.
• Free tier included: available to Free, Go, Plus, Pro, Business, Enterprise, Edu and K-12 users globally. Free and Go get "limited usage access".
• It spends your allowance: a typical PowerPoint task on GPT-5.5 may burn 10 to 50 credits per message, and Word usage reduces what is left for Codex.
• It works on a Mac, with Microsoft's floors at Word 15.18, Excel 15.19 and PowerPoint 15.24.
• Turns on by itself: from 1 October 2026 ChatGPT for Word is enabled by default.

What the ChatGPT Excel Add-In Actually Is

It is a sidebar. You open a workbook, open ChatGPT from the ribbon, and type in plain language. The difference from pasting a table into the chat window is that the model works on the live file. It can build a tracker from scratch, trace why cell B145 is throwing an error, clean up inconsistent labels, or run a scenario and then report back which cells it changed.

One Add-In, Not Three

This trips people up, so it is worth stating clearly. OpenAI's own FAQ answers the question "Do I need a separate add-in for Word?" with a flat "No. Word, Excel, and PowerPoint use the same ChatGPT Microsoft add-in." The Marketplace listing is the same product ID in all three cases. Install it once and it appears in all three ribbons.

It Is Probably Not the One Google Shows You

Search for a ChatGPT Excel plugin and most of the first page is something else. The tutorials that rank best were written in 2023, before any of this existed. They walk you through pasting VBA into the macro editor, or signing up for a third-party add-in that asks for your OpenAI API key. Those products are real and some are good, but they are not OpenAI's, they bill separately, and a key is a developer credential most people should not be creating to format a spreadsheet.

The official one is published by OpenAI, is simply called ChatGPT in the Marketplace, and asks you to sign in with the ChatGPT account you already have. If a page tells you to paste an API key, you are looking at a different product.

How to Install the ChatGPT Excel Add-In

The path differs slightly by app, and OpenAI documents both.

In Excel

1. Open Microsoft Excel, desktop or web.
2. Go to Home, then Add-ins.
3. Search for ChatGPT.
4. Add it, then open ChatGPT from the ribbon.
5. Sign in with the ChatGPT account on your plan.

In Word and PowerPoint

Same add-in, so if you did the Excel step you are already done. Coming at it fresh, open the ChatGPT listing on Microsoft Marketplace, select Get it now, follow the steps, then open ChatGPT from the ribbon and sign in.

In Google Sheets

The story is not Microsoft-only. There is a separate ChatGPT app in the Google Workspace Marketplace, opened from the Extensions menu in Sheets. OpenAI describes Excel and Sheets as "separate spreadsheet experiences" that support similar workflows, so treat them as two installs rather than one product in two places.

Does It Work on a Mac?

Yes, and this is worth pinning down because almost nobody states it. Neither OpenAI page names an operating system at all. Microsoft's own developer documentation does: the minimum client versions of Office on Mac that support Office Add-ins are Word 15.18, Excel 15.19 and PowerPoint 15.24. Any reasonably current Microsoft 365 install on macOS clears those comfortably. If you are running a boxed copy from the Office 2016 era, check your build number before assuming.

What It Actually Costs

This is the section the rest of the internet skipped, and it is the one that matters.

Free on every plan is a true statement about availability and a misleading one about use. OpenAI's spreadsheet documentation says the add-in is available globally to Free, Go, Plus, Pro, Business, Enterprise, Edu and K-12 users, and then immediately qualifies it: "Free and Go include limited usage access. Plus and Pro include access subject to your plan's agentic usage limit."

The Number OpenAI Published

The PowerPoint documentation is the only one that puts a figure on it, and it is a useful anchor for all three apps: "A typical ChatGPT for PowerPoint task using GPT-5.5 may consume between 10 and 50 credits per message." Bigger decks, multi-step edits and source-grounded requests cost more. The same token-based rates apply to Excel and Sheets.

The Trade-Off Nobody Mentions

For Word, OpenAI is blunt about where the money comes from: "Word uses token-based pricing at the API rates for the model you use," and "Word draws from the shared usage allowance for Codex and other premium features on plans that include it. Using Word can reduce the included usage available for those other features."

Read that twice if you use Codex. Reformatting a long document in Word is not free in the sense of costing nothing. It is spending from a pot you probably rely on elsewhere. If you are already bumping into ceilings, our guide to how ChatGPT's limits work and when they reset explains the shared-allowance mechanics in more detail.

What It Can and Cannot Do

The limitations are documented, and they are more interesting than the feature list.

The Memory Gap Is the Real One

Losing VBA support is an edge case for most people. Losing memory and history is not. The version of ChatGPT in your spreadsheet does not know what you have told the version in your browser. House style, recurring context and anything you have taught it over months are simply not there. Every session starts cold. That is a reasonable privacy design and a genuine daily annoyance, and it is the single biggest reason the add-in complements a chat app rather than replacing one.

What Microsoft and OpenAI Can See

Buried in the spreadsheet documentation is a sentence that deserves more attention than it has had: "As part of Microsoft's Add In Marketplace Terms of Service, Microsoft may have the ability to read the content of your Excel workbook, attachments, and prompts."

That is OpenAI telling you, in its own help centre, that running its add-in inside Microsoft's product brings Microsoft's terms along with it. Separately, OpenAI says it might store some of your data logs for 30 days "for safety and integrity purposes", and that in Business, Enterprise and Edu workspaces inputs and outputs are not used for training by default.

None of that is alarming for a budget tracker. It is worth a pause before you point it at a workbook full of salary data or client financials.

The 1 October Change You Should Know About

One dated detail: "Starting October 1, 2026, ChatGPT for Word will be enabled by default." If you have not installed anything, the sidebar can still appear.

Two gates control it, and they are separate. Workspace admins turn ChatGPT for Word on or off in the ChatGPT admin console, and Microsoft 365 admins must also allow the add-in for it to show up at all. If ChatGPT never appears in your ribbon at work, that second gate is almost always the reason, not a bug. On a personal Mac, you remove it the way you remove any Office add-in.

How This Changes the Copilot Question

Microsoft's pitch for Copilot has always leaned on location: it is the AI that lives where you work. That argument just got weaker, because a free ChatGPT account now also lives where you work.

It is not a clean win. Copilot is wired into your Microsoft 365 tenant, your mail and your files in a way the add-in explicitly is not, and the add-in cannot see other documents on your machine. But for someone paying for Copilot mainly to get AI inside Word and Excel, the calculation has changed. We cover the wider comparison in Microsoft Copilot vs ChatGPT, and the free-tier question in our guide to what Copilot actually gives you for nothing. Anthropic has its own entry in this space too, covered in Claude for Excel.

When You Want the File, Not the Sidebar

The add-in is built around a document you already have open. A lot of the time that is not the job. The job is producing a spreadsheet out of a mess of notes, or turning a pile of research into a deck, and for that you do not want to open Excel first and then ask for help inside it.

That is where Fello AI fits. It runs natively on Mac, iPhone and iPad, and it creates real Word, Excel, PowerPoint and PDF files as output, so you describe what you need and get the document back rather than a wall of text to reformat. It also keeps GPT, Claude, Gemini, Perplexity, Grok, Kimi, DeepSeek, GLM and Qwen behind one subscription, which matters when a spreadsheet task and a writing task want different models.

There is a free tier, and the paid plan is $9.99 a month or $79.99 a year for the whole roster, against 4.7 stars from more than 27,000 reviews. The honest split is this: for editing a workbook that already exists, the official add-in sitting in the ribbon is the better tool. For producing the file in the first place, or for anything that needs memory and a model of your choosing, a proper chat app is.

The Verdict

Install it. It costs nothing to add, it is OpenAI's own rather than a third-party wrapper asking for an API key, and letting the model see the live workbook instead of a pasted screenshot is a real step up for spreadsheet work.

Just go in with the right expectations. It is metered, not free, and on a paid plan it quietly competes with Codex for the same allowance. It has no memory and no history, so it will never feel like the assistant you have been training all year. And from 1 October it will show up in Word on its own, which is a good reason to decide now whether you want it there. For the wider job of actually using AI on this kind of work, our complete guide to using AI in Excel and its companions for Word and PowerPoint go further than a sidebar can.

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