Copilot vs ChatGPT: what the Bing index changes

One quick disambiguation before anything else: this page is about Microsoft Copilot, the assistant in Windows and Microsoft 365. GitHub Copilot is a separate product for writing code, and nothing below applies to it.

The short answer

Choose Copilot if your company already runs on Microsoft 365, because the value comes from its access to your documents, email and meetings. Choose ChatGPT if you want the strongest general assistant, independent of your office suite. On the brand visibility side, working one moves the needle on the other, and that is genuinely rare.

The comparison table

Licensing terms and list prices move often on both sides, so treat any figure you find as indicative and check the current terms with the vendor.

What ChatGPT does better

ChatGPT is more agile in open conversation, richer in third party integrations, and faster to ship whatever OpenAI builds next. It is also independent of your software stack: you can adopt it without changing anything about how your company is set up. And its audience makes it the largest single exposure surface a brand can work on.

What Copilot does better

Copilot has one advantage no consumer assistant can copy: it sees your data. Drafting from an email thread, summarizing a meeting, finding an internal document, cross referencing a spreadsheet with a report, all of that happens without copy paste and without your information leaving your tenant. In a regulated or privacy sensitive environment, that is usually the deciding factor, and it is not a small one.

The verdict by use case

• You are a Microsoft 365 shop: Copilot, for the value it unlocks on your own data.
• You want a versatile assistant: ChatGPT.
• You have hard confidentiality constraints: Copilot, inside your tenant boundary.
• You are testing your brand visibility: start with ChatGPT, the findings will transfer to Copilot better than to any other engine.
• You want coding help: neither of these two, that is GitHub Copilot's territory.

What this changes for your brand visibility

This is the most useful takeaway on the page. Because both engines sit on the Bing index, visibility work that lifts you in ChatGPT mechanically lifts you in Copilot, minus the drift that comes from the two products being used differently. That is the exception that proves the rule: normally, visibility in one engine does not transfer to the next at all.

In practice it means paying attention to what Bing sees of your site: clean indexation, fresh pages, clearly identified entities, and off site brand mentions. Microsoft also ships Bing Webmaster Tools free of charge, and it now includes reporting on how your site performs in AI experiences, which is one of the few first party windows on any of this. Use it. It will not tell you what ChatGPT says about you, but it tells you what Bing knows about you, and that is the shared input.

Do not stretch the conclusion too far though. Two products on one index still return different answers to the same question, because the usage context differs. And the shared index logic stops at the property line: Perplexity built its own index, and Gemini runs on Google's, so neither inherits anything from your Bing footprint. The underlying discipline is still mostly clean technical foundations and good content, which is why GEO extends SEO rather than replacing it.

Sources

• John Mueller (Google) via Search Engine Land: solid SEO fundamentals remain the key to AI visibility
• Forrester, 2026 Buyer Insights (survey of 18,000 buyers): 94 percent of B2B buyers used AI during their most recent purchase
• Princeton, GEO: Generative Engine Optimization (KDD 2024): citing sources and adding statistics raises visibility in AI answers by 22 to 41 percent

Two products, one index, answers that still do not always line up. To see what each of them says about your category, request a free AI visibility audit: AIVIIU measures your visibility across the main engines and identifies the competitors getting named in your place.