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AI Overviews vs ChatGPT vs Perplexity for B2B discovery

“AI search” is not one channel. Google AI Overviews, ChatGPT and Perplexity reach different audiences, retrieve pages differently, and cite different sources. Treating them as one number hides where you actually win or lose.

·7 min read·By the ZivRank team

Reach: three very different audiences

Google’s AI features have the widest reach because they sit inside Search. ChatGPT has the largest standalone assistant audience. Perplexity is smaller.

EngineLatest official figureSource
Google AI OverviewsOver 2 billion monthly users (July 2025)Google [1]
Google AI ModeAbove 1 billion monthly active users (July 2026)Google [2]
ChatGPTMore than 900 million weekly active users (February 2026)OpenAI [3]
Perplexity780 million queries in May 2025, stated by its CEOTechCrunch [4]

These figures are self-reported, measured differently (users vs queries, monthly vs weekly) and cannot be compared directly. We found no primary source for more recent Perplexity volumes.

How each engine finds and cites pages

All three retrieve web pages at answer time, but they do it through different systems and show sources differently.

  • Google AI Overviews and AI Mode use a “query fan-out” technique, “issuing multiple related searches across subtopics and data sources”. Google states “there are no additional requirements to appear in AI Overviews or AI Mode” beyond being indexed and eligible for a snippet [5].
  • ChatGPT search rewrites the question into targeted queries sent to search providers; “responses that use web search may include citations”, and “placement is not guaranteed” [6].
  • Perplexity says content “is sourced from the web in real-time as you ask your questions” [7], and shows its sources with each answer.

How much they overlap with Google rankings

AI Overviews draw more on pages that rank in Google than the assistants do, but less than they used to.

  • Ahrefs found 37.9% of URLs cited in AI Overviews also appeared in the top 10, in an analysis published in March 2026. Its July 2025 analysis had found about 76% [8].
  • seoClarity found AI Overview citations overlapping the top 10 32% of the time, rising to 89% when only one source is cited, across 362,000 US queries [10].
  • For assistants, Ahrefs found only 12% of links cited by ChatGPT, Gemini and Copilot ranked in Google’s top 10 for the same prompt; Perplexity was the exception at about 28.6% [9].

Studies differ in method and timing, so the exact numbers vary. The direction does not: a top-10 ranking is neither necessary nor sufficient.

What we see when we measure them separately

The same work can move one engine and leave another flat. That is why we never report a single blended score.

In our published case study, a US B2B SaaS vendor, we tracked Google AI Overviews separately from the four assistants, on 250 searches per period. The client’s site went from outside the top 10 sources cited in AI Overviews to 6th, and the number of AI Overview blocks citing the client went from 26 to 35. Over the same period, ChatGPT did not move. See the full case.

What to do with this

  • For AI Overviews: classic search hygiene still counts (indexing, snippet eligibility, clear answers), and Search Console reports this traffic under “Web” [5].
  • For ChatGPT: allow OAI-SearchBot, answer narrow questions precisely, and be present on the third-party pages it reuses. The ChatGPT playbook.
  • For Perplexity: its visible sources tell you exactly which pages to be on. What Perplexity cites.
  • For all three: one fixed question set, several runs per engine, one line per engine in the report.

Frequently asked questions

Which AI engine matters most for B2B?
It depends on your buyers, which is why each engine should be measured separately. Google AI Overviews reach the most people because they sit inside Google Search; ChatGPT has the largest assistant audience; Perplexity is smaller but cites its sources on every answer.
Do I need to rank in Google to appear in AI Overviews?
Your page must be indexed and eligible for a snippet; Google states there are no additional requirements. Ranking in the top 10 helps but is not required: in Ahrefs’ 2026 data, about 38% of AI Overview citations came from top-10 pages.
Are AI Overviews and AI Mode the same thing?
No. AI Overviews appear at the top of regular Google results; AI Mode is a separate conversational search experience. Google documents both on the same page and uses the same Search controls for them.
Does Perplexity always cite sources?
Perplexity describes itself as sourcing content from the web in real time for each question, and its answers link to sources. That makes it the easiest of the three engines to audit.

Sources

Every figure in this article comes from the sources below, checked on October 11, 2026. Bracketed numbers in the text refer to this list.

  1. [1] Google, Q2 earnings call: CEO’s remarks (2025), July 23, 2025.
  2. [2] Google, Q2 2026 earnings call: Remarks from our CEO, July 22, 2026.
  3. [3] OpenAI, Scaling AI for everyone, February 27, 2026.
  4. [4] TechCrunch, Perplexity received 780 million queries last month, CEO says, June 5, 2025.
  5. [5] Google Search Central, AI features and your website, last updated December 10, 2025.
  6. [6] OpenAI Help Center, Searching the web with ChatGPT, checked October 11, 2026.
  7. [7] Perplexity Help Center, What is Perplexity?, undated, checked October 11, 2026.
  8. [8] Ahrefs (Louise Linehan), Update: 38% of AI Overview Citations Pull From The Top 10, March 2, 2026.
  9. [9] Ahrefs (Louise Linehan), Only 12% of AI Cited URLs Rank in Google’s Top 10 for the Original Prompt, August 11, 2025.
  10. [10] seoClarity, AIO rankings overlap research, October 2025.