AI tools compared · Guide
Copilot vs ChatGPT vs Claude for accountants: which fits your firm?
Choosing Copilot vs ChatGPT vs Claude for accountants comes down to where the work happens. Microsoft Copilot works inside Microsoft 365 and Excel under your existing permissions. ChatGPT Business and Claude Team are standalone assistants with their own admin controls and Microsoft 365 connections. None trains on business data by default, but they store data in different places.
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- Peter
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Which one should an accounting firm choose?
Choose by where your staff spend their day and how sensitive the work is, not by which chatbot wins a benchmark this month. All three are built on capable large language models, and all three offer business plans that keep your data out of model training by default. The differences that matter to an accounting firm are integration, admin controls and where data sits.
- Your firm lives in Outlook, Teams, SharePoint and Excel, and your file permissions are tidy: start with Microsoft Copilot.
- You want a strong general assistant for drafting, research and analysing uploaded files, across more than Microsoft tools: trial ChatGPT Business and Claude Team side by side with the same tasks.
- Client files cannot go into a public AI tool at all: look at private AI and knowledge assistants instead of any of the three.
Whichever you pick, the setup decides whether it is safe. Our AI Setup service configures any of these plans properly: single sign-on, admin controls, training opt-outs, connectors, a prompt library, a usage policy and team onboarding.
How do the business plans compare in September 2026?
The table compares the business tiers as described in each vendor’s own documentation in September 2026. Microsoft has renamed Microsoft 365 Copilot as Microsoft Copilot, and all three products change often, so check the linked sources before you buy.
| Microsoft Copilot | ChatGPT Business and Enterprise | Claude Team and Enterprise | |
|---|---|---|---|
| How you buy it | A per-user add-on to an eligible Microsoft 365 plan. Microsoft Copilot Business is an add-on for Business Basic, Standard and Premium. Web-grounded Copilot Chat is included with eligible plans at no extra cost. | Business: standard and premium seats for 2 to 200 people. Enterprise: through OpenAI sales. | Team: per seat for 2 to 150 people, with standard and premium seats. Enterprise: seat fee plus usage at API rates. |
| Microsoft 365 and Excel | Built into Word, Excel, PowerPoint, Outlook and Teams, grounded in the email, files and chats each user can already open. | A separate app. Apps connect to Microsoft 365 and other tools, subject to admin settings. Excel and PowerPoint extensions are included on Business and Enterprise. | Add-ins for Excel, Word and PowerPoint on all paid plans, with Outlook in beta. A Microsoft 365 connector searches SharePoint, OneDrive, Outlook and Teams, read-only by default. |
| Sign-in and admin | Your existing Microsoft Entra accounts. Retention and audit through Microsoft Purview; sensitivity labels are respected. | Business: SAML single sign-on and MFA; no SCIM. Enterprise adds SCIM, role-based access, key management and audit logs through the Compliance API. | Team: single sign-on, central admin and connector controls. Enterprise adds SCIM, audit logs, role-based access, a Compliance API and IP allowlisting. |
| Training default | Prompts, responses and Microsoft Graph data aren’t used to train foundation models. | No training on business data by default. | No training on commercial content by default, unless users submit feedback. |
| Where data sits | Interaction content stored at rest in Australia for tenants that signed up in Australia. Processing may occur in other regions. | Enterprise and Edu: data residency in ten regions, including Australia, for new workspaces; inference residency is not offered in Australia. Business: no residency option. | Stored in the US. Traffic may be routed to the US, Europe, Asia or Australia. |
| Retention controls | Purview retention policies. | Enterprise: data retention controls. | Enterprise: custom retention controls. Team: standard retention. |
Sources: Microsoft’s Copilot privacy documentation, licensing and data residency pages; OpenAI’s ChatGPT Business and Enterprise pricing and data residency pages; Anthropic’s Claude pricing and server location pages.
What does each one cost?
All three charge per person per month, but they are built on different foundations. Copilot is added on top of Microsoft 365 licences the firm already pays for. ChatGPT and Claude are separate subscriptions, and both now sell standard and premium seats at matching list prices.
As at September 2026, OpenAI lists ChatGPT Business standard seats at $20 per user per month billed annually or $25 monthly, and premium seats at $100 or $125; ChatGPT Enterprise is priced through its sales team. Anthropic lists Claude Team standard seats at $20 per seat per month billed annually or $25 monthly, premium seats at $100 or $125 per seat per month, and Claude Enterprise at US$20 per seat per month, billed annually, plus usage at API rates. These are US-dollar list prices, and local tax may apply. Microsoft’s Copilot and Copilot Business prices depend on your plan and how you buy, so check Microsoft’s current figure for your agreement.
The licence fee is only part of the cost. The part that varies is setup and ongoing admin: permissions, policies, training and keeping the configuration right as the vendors change their products.
What should accountants check before switching one on?
Six checks cover most of the risk, and they apply whichever tool you choose.
- File permissions. Copilot only surfaces content a user can already open, and Claude’s Microsoft 365 connector mirrors each user’s existing permissions. Both depend on SharePoint and OneDrive sharing being tidy. An “everyone” link on a folder of client tax returns becomes easy to find.
- Which models your tenant uses. Microsoft now offers Anthropic’s models inside Copilot. According to Microsoft’s documentation, they are on by default for most commercial tenants outside the EU, EFTA and the UK, which covers most Australian tenants, and they are currently excluded from Microsoft’s in-country processing commitments where those apply. Admins can turn them off. Anthropic models that require data retention by Anthropic stay off until an admin opts in.
- Sign-in and offboarding. Connect sign-in to Microsoft Entra so access ends when someone leaves. On ChatGPT Business and Claude Team there is no SCIM, so removing a departing staff member’s seat is a manual step that needs to be on the exit checklist.
- Retention and audit. Decide how long chats are kept and who can search them. Copilot uses Purview; the ChatGPT and Claude enterprise tiers have their own retention and audit controls, and the business tiers have fewer.
- Client permission. Under the Tax Agent Services Act 2009, a registered agent must not disclose a client’s information to a third party without permission unless there is a legal duty to. The TPB’s July 2026 guidance, TPB(GS) 55/2026, explains how the Code applies to AI tools. Check your engagement letters.
- Zero data retention. This is mainly an API arrangement. Anthropic, for example, offers it by agreement for eligible Claude API features and for Claude Code, but the Claude Team and Enterprise chat interfaces are not eligible. Firms that need it are usually building their own tools, not buying seats.
Our guide to setting up ChatGPT Business securely walks through these settings for one product. If staff are already using personal AI accounts, deal with that first; our article on shadow AI in professional firms covers how.
Which accounting tasks suit each tool?
Each tool is strongest where it can see the right context. The table gives a starting point for a trial, not a verdict.
| Task | A sensible first tool to try | Why |
|---|---|---|
| Explaining variances in a management accounts workbook | Copilot, Claude or ChatGPT in Excel | All three work inside the workbook, so staff don’t paste figures into a separate chat |
| Summarising a Teams client meeting and drafting the follow-up email | Copilot | It already has the meeting and the Outlook thread |
| Pulling key terms out of a long trust deed or partnership agreement | ChatGPT or Claude | Both accept long uploaded documents for analysis |
| First draft of an engagement letter from your firm’s template | Any of the three | The partner review matters more than the tool |
| A weekly partner report on WIP and utilisation | None on its own | This needs a data pipeline; see Power BI vs Xero reporting |
Anything that reaches a client or the ATO still needs review by a registered practitioner. The TPB’s guidance says practitioners remain accountable for their work when they use AI.
Example: a 30-person firm on Microsoft 365 Business Premium
Illustrative scenario: a 30-person firm already runs Microsoft 365 Business Premium, keeps client files in SharePoint and has a few staff paying for personal ChatGPT accounts. A sensible path is to tidy SharePoint sharing first, switch on Copilot Chat for everyone, decide on the Anthropic model setting, and license Copilot Business for the managers who spend their day in Excel and Outlook. Then run a four-week trial of ChatGPT Business or Claude Team with five staff on the same set of tasks, and decide on one paid assistant with the results in front of the partners.
This is general information, not tax or legal advice.