Copilot vs ChatGPT: which assistant fits an accounting or finance team

Copilot vs ChatGPT at a glance

Copilot and ChatGPT aren't rival versions of one product. Microsoft builds Copilot on OpenAI models (and now Anthropic's), but the two are sold, governed and documented separately, so the plan terms below apply to each one on its own.

What Copilot and ChatGPT cost

Two things make the sticker prices less comparable than they look. Microsoft's Business Standard and Business Premium bundles include the Microsoft 365 apps themselves, while a ChatGPT seat is for ChatGPT alone. And both companies now meter some agent work on top of the seat: Microsoft says "Advanced AI—work you hand off—is billed as you use it," and OpenAI says ChatGPT for Excel draws on each plan's agentic usage limit and credits. Check the Microsoft (opens in a new tab) and OpenAI (opens in a new tab) pages before you budget, since both change often.

What each company says about your data

For accounting work this is usually the deciding question, and the answer depends more on the plan than on the brand.

Copilot with a work account

Microsoft says prompts, responses and data accessed through Microsoft Graph "aren't used to train foundation LLMs," and that Copilot "only surfaces organizational data to which individual users have at least view permissions." Admins can set retention for Copilot chats in Microsoft Purview (Microsoft Learn (opens in a new tab)). That makes your SharePoint and Teams permissions the real control: Copilot will find a client file anyone in the firm can already open.

The Copilot app with a personal account

Microsoft says prompts, responses and file contents in the Microsoft Copilot app aren't used to train foundation models (Microsoft Support (opens in a new tab)). It's still a personal account, outside your firm's retention, access and e-discovery controls.

ChatGPT Business and Enterprise

OpenAI says "We do not train our models on your data by default" for Business, Enterprise, Edu and the API, that Business completed a SOC 2 Type 2 audit, that Business admins control retention, and that deleted or unsaved conversations are removed within 30 days, with limited exceptions such as legal requirements (OpenAI (opens in a new tab)).

ChatGPT Free, Plus and Pro

On personal workspaces "data sharing is enabled by default." You can turn off "Improve the model for everyone" under Settings, Data controls; temporary chats aren't used to improve OpenAI's models but may be kept up to 30 days. OpenAI also notes that if you give feedback, such as a thumbs up or down, the whole conversation may be used for training (OpenAI Help Center (opens in a new tab)).

The same rule applies to both: business terms protect only what goes through the business account. A staff member pasting a client's trial balance into a personal ChatGPT or Copilot account is outside them.

Copilot vs ChatGPT in Excel

Copilot is built into Excel for users with a qualifying Microsoft 365 plan, and Microsoft lists it in the Business and enterprise Copilot plans above. How it works in a workbook, and which licenses include it, are in Copilot in Excel.

ChatGPT reaches Excel through the ChatGPT for Excel add-in, which OpenAI lists for Free, Go, Plus, Pro, Business, Enterprise, Edu and K-12 users, with limited use on Free and Go. OpenAI says it asks permission before changing a workbook and links answers to the cells it used. It ships with default skills for financial modeling and corporate finance formatting, can use the apps your ChatGPT account connects to, and may not fully support VBA and macros (OpenAI Help Center (opens in a new tab)).

One detail matters for client data: OpenAI notes that under Microsoft's add-in marketplace terms, Microsoft may be able to read the workbook content, attachments and prompts. So the ChatGPT add-in involves both companies' terms, not just OpenAI's. The three Excel assistants, including Claude, are compared side by side in Best AI for Excel.

Finance and accounting features

Copilot: the Finance Agent

Microsoft's Finance Agent works in Excel, Outlook and Copilot chat. In Excel, the Financial Reconciliation agent compares two tables and writes a reconciliation report with suggested next steps. In Outlook, it supports collections, with ERP connections for Dynamics 365 Finance, SAP and other systems. Microsoft says its interface and AI-written content are in US English only for now (Microsoft Learn (opens in a new tab)). What's generally available and what's in preview is in Copilot for Finance.

ChatGPT: financial data and research

OpenAI has added apps for financial data, naming Moody's, Dow Jones Factiva, MSCI, Third Bridge, MT Newswires, FactSet, LSEG, Daloopa and S&P Global, and supports your own data through Model Context Protocol (MCP) apps. Research in ChatGPT can pull from filings, transcripts and spreadsheets and export cited output to PDF or Word (OpenAI (opens in a new tab)). Its uses and limits for accountants are in ChatGPT for accounting.

Neither one is an accounting system. Copilot's reconciliation produces a report, not journal entries, and ChatGPT doesn't post to your ledger unless a connected tool lets it. For work on the books themselves, several accounting tools in the directory connect their data to one or both assistants:

Once a tool is connected, the assistant plan's data terms cover what it reads, so connect from business accounts only.

Which to choose

Your firm runs on Microsoft 365

Start with Copilot Chat, which costs nothing extra, then license Microsoft 365 Copilot for the people who need it in Outlook, Excel and Teams. Clean up SharePoint and Teams permissions first, because Copilot will surface whatever a user can already open.

Your team works across Google Workspace, Microsoft 365 or both

ChatGPT Business connects to both, and its Excel and Google Sheets add-ins cover both spreadsheet tools. Turn on only the connectors you need, and set retention in the workspace settings.

You do model-heavy FP&A or deal work

ChatGPT's financial data apps and modeling skills are aimed at this. Copilot's Researcher and Analyst agents and the Finance Agent cover more of the operational side: reconciliation and collections.

Staff already use personal accounts

Either business plan is a step up from that. Pick one, block or discourage personal accounts for client work in your AI policy, and train staff on what not to paste.

If you pay for both, say Copilot for the Microsoft 365 work and ChatGPT for analysis and research, write down which one is approved for which data.

Before you use either with client data

For a policy to adapt, see the AI acceptable use policy template. Tax preparers should also read Section 7216 consent for AI.