ChatGPT Enterprise vs Copilot: pricing, cost per user and the seat limits each vendor actually publishes

Microsoft can be priced exactly, because every component is published. OpenAI cannot, because the Enterprise price does not exist in public. So the only intellectually honest comparison is Microsoft's real all-in seat against ChatGPT Business, which is the largest OpenAI plan with a published price, and then a clearly labeled band for Enterprise.

Two things jump out of that table. The first is that ChatGPT Business is dramatically cheaper per seat than a fresh Microsoft enterprise stack, and it is not close. The second is that the comparison is not like for like, because most companies buying Copilot already pay for E3 or E5 and would pay for it with or without AI. If you already own the base license, Copilot's marginal cost really is $30.00, and on that basis Microsoft is the cheaper AI decision by $10.00 a seat.

That is the single question that decides this comparison, and it is a procurement question rather than a product one: are you adding AI to a suite you already own, or buying a suite in order to get the AI? Ask it before you compare a single feature.

Microsoft's own pricing page carries the qualifier in a footnote: a separate license for a qualifying Microsoft 365 plan is required to purchase Microsoft 365 Copilot. Copilot is not sold standalone at any tier. The published enterprise base plans, read on September 4, 2026, are E3 at $39.00, E5 at $60.00, E7 at $99.00 and a variant Microsoft now lists as E7 (No Teams) at $90.45.

The E7 line is worth a moment, because it changes the arithmetic for anyone shopping at the top. Microsoft describes E7 as including Microsoft 365 E5, Copilot, Agent 365 and Microsoft Entra Suite in one SKU. At $99.00 it sits $9.00 above buying E5 and the Copilot add-on separately, and for that $9.00 you also get Agent 365 and the Entra Suite. If you were already going to buy all four, E7 is the cheaper line item, and a lot of quotes still price them individually.

The other omission is the promotional window. Copilot Business currently shows as originally starting from $21.00, now starting from $18.00 per user per month paid yearly. Microsoft's footnote is specific about the terms: the discount is available between July 1, 2026 and December 31, 2026, the add-on is available only to existing Microsoft 365 customers with an eligible Business plan, an annual commitment is required, and promotional pricing applies to the first year only. There is a seven day cancellation window for a prorated refund, it does not apply to trial subscriptions, and it cannot be combined with another offer.

Read that last clause carefully if you are budgeting past next year. Year one is $18.00. Year two, on today's list, is $21.00, a 16.7 percent increase you should put in the model now rather than discover at renewal.

OpenAI's Business FAQ is unusually direct about the ceiling. Verbatim: starting on Aug 24, 2026, the maximum is 200 paid Standard and Premium seats total per ChatGPT Business subscription, and our support team is unable to change your maximum seat limit. The limit counts purchased seats including unassigned ones, invitations do not reserve a seat, and workspaces created before that date retain their previous seat limit.

So a company that was on ChatGPT Business before August 24 may still be able to grow past 200, and one that signed up afterwards cannot. That distinction is missing from every comparison article we could find, and it is the difference between a renewal and a migration.

The minimum is the opposite situation. Search for ChatGPT Enterprise minimum seats and you will be told, confidently and everywhere, that OpenAI requires 150 seats and charges $45.00 to $75.00 per seat. OpenAI publishes none of that. The only seat-count statement on its plan FAQ is that Business plans are available starting at 2 users and that you should contact sales to learn more about the Enterprise plan. The 150 seat figure and the price band come from procurement databases and resellers, they may well reflect real deals, and they should be labeled as secondary every single time. We label them.

There is one more Enterprise trap worth knowing before you sign, because it inverts the usual assumption that a bigger contract buys more headroom. OpenAI states that Enterprise and Edu plans without flexible pricing have the same per-seat usage limits as Plus for most features. Paying enterprise rates does not automatically buy enterprise usage. Usage comes from the workspace credit pool, and when that pool empties, advanced features pause unless workspace owners have enabled overages.

Price gets a purchase approved. Coverage decides whether anyone still uses the thing in month three, and this is where the two products diverge more than any pricing table shows.

Copilot works inside the Microsoft Graph. If your documents live in SharePoint and OneDrive, your discussions in Teams and your correspondence in Outlook, Copilot sees them, honors the permissions already set on them, and answers well. If a meaningful share of your institutional knowledge lives in Slack, Notion, Confluence, Jira or Salesforce, Copilot does not reach it natively, and no amount of licensing changes that.

ChatGPT reaches company data through what OpenAI now calls the Company Knowledge plugin, which as of a recent update replaces the previous company knowledge option in chat. The supported sources include Slack, Google Drive, SharePoint, GitHub, HubSpot, OneDrive, Box and Dropbox, which is a genuinely wider net than Microsoft's. The catch is in how access is granted. OpenAI states it twice, plainly: installing the plugin does not connect your app accounts, and plugin installation does not connect individual app accounts or grant access to source data. Members authenticate a provider account when the selected app requires individual authorization, with a supported administrator-managed Google Drive source as the documented exception.

That is the structural point. Coverage is per person and opt-in. An admin can install the plugin for the whole company and still have a company where nobody's Confluence is connected, because each person has to complete an OAuth flow for each app. It is an assistant that borrows each user's access, not an index of what the organization knows.

Credit where it is due on both sides: permissions are handled correctly. Copilot inherits Microsoft 365 permissions. OpenAI states that a member can retrieve only information they are already allowed to access, that the plugin does not override workspace access controls or app permissions, and Enterprise admins get RBAC, group-level permissions, SSO and SCIM. Nobody here is leaking documents. The question is coverage and control, not safety.

Four situations cover most US buyers, and in three of them the answer is not us.

You already pay for E3 or E5 and your work really does live in Microsoft. Buy Copilot. The marginal cost is $30.00, it is embedded in the apps people already have open, and there is no new vendor, no new security review and no new login. This is the strongest case in the comparison and it is not close.

You are under 300 users, on a Microsoft 365 Business plan, and deciding this quarter. Copilot Business at $18.00 is the cheapest governed AI seat either vendor sells, and the promotion ends December 31, 2026. Model year two at $21.00 before you sign, and remember the 300 user ceiling is a real wall, not a soft limit.

You want the strongest general assistant and your stack is mixed. ChatGPT Business at $20.00 is excellent value and genuinely better at open-ended work than Copilot is today. Watch the 200 seat ceiling if you are growing, and treat any Enterprise quote as a negotiation with no public anchor.

Your problem is that nobody can find anything. This is the case neither product solves well, and it is the one we built for. If the recurring complaint is that the answer existed in Confluence and a Slack thread and a Drive doc and nobody found it, an assistant that borrows one person's logins at a time is not the shape of the fix. You need an index.

InSearch does one job: it searches Google Drive, Slack, Notion, Confluence, Gmail, Jira and Salesforce together and returns a written answer with inline citations back to the exact source. It is permission-aware by design, so nobody sees an answer built from something they could not already open, and it never trains on your data. Team is $20.00 per user per month, Business is $32.00 and Scale is $49.00, all billed annually.

Against the Microsoft all-in seat of $69.00 or $90.00, that is a straightforward saving. Against ChatGPT Business at $20.00, it is a different purchase rather than a cheaper one, and it is worth being honest about that. ChatGPT will write your board deck and debug your SQL. We will not. If you want one tool that does everything an assistant does, buy the assistant.

What we do that neither of them does is give one admin one index across the apps the company actually uses, without asking each employee to authorize each connector personally. Plenty of companies end up buying both, and that is a reasonable outcome: the assistant for open-ended work, the index for finding things. If that sounds like your situation, the permission-aware AI search page covers how the access model works, and unified search covers the query side.