The real search engine market share of ChatGPT

The prevailing narrative about ChatGPT's low search volume might be wrong - and the gap is significant enough to change how you think about AI visibility.

According to data from Ahrefs' AI vs Search Traffic Analysis tool, ChatGPT represents just 0.6% of Google's search volume based on outgoing traffic to websites. But when you dig into actual usage data and adjust for how these platforms work differently, the picture changes dramatically. ChatGPT appears to be somewhere between 2% and 12% of Google's size - significantly larger than click data suggests.

We found this result using two different ways of calculating that both point to the same answer.

The problem with click data

Ahrefs tracks how many clicks websites receive from Google versus ChatGPT. Their data shows that for every 4,135 clicks a website gets from Google, it gets just 24 clicks from ChatGPT. That's a ratio of roughly 172:1, suggesting ChatGPT is 0.6% the size of Google.

But there's a fundamental issue with this approach: Google and ChatGPT have completely different user experiences.

Google shows blue links that practically demand clicks. ChatGPT provides complete answers that rarely require visiting external sites. When you measure these platforms by clicks alone, you're only counting the times users needed more information - not the times they got their answer directly.

This means comparing outgoing clicks systematically underestimates ChatGPT's actual search volume. The question is: by how much?

Method 1: The OpenAI study

In September 2025, OpenAI and Harvard published research revealing that ChatGPT sees 2.5 billion prompts per day. Of those, 24% can be classified as search queries (”seeking information”) - people looking for information rather than asking the AI to generate content or provide assistance with tasks.

The math is straightforward:

• 2.5 billion total prompts per day

• × 24% search queries

• = 600 million searches per day on ChatGPT

Google processes approximately 14 billion searches per day. That puts ChatGPT at roughly 4.3% of Google's search volume.

One common objection: doesn't ChatGPT require multiple messages per query? Some data suggests users send an average of 8 messages per conversation. If we divided by 8, ChatGPT would be just 0.5% of Google.

But that 8-message average includes all ChatGPT usage: people writing essays, generating images, debugging code. For simple search queries ("What's the capital of France?" or "Who won the election?"), the back-and-forth is minimal. Based on the real user prompts we are seeing in clickstream data, most search queries need less than 2 messages, not 8.

So we will use the 600 million number as our starting point and see if other approaches confirm it.

Method 2: Referral traffic (clicks)

Let's work backwards from that Ahrefs data using what we know about click-through rates.

Start with the raw numbers:

• A website gets 4,135 clicks from Google

• The same website gets 24 clicks from ChatGPT

Studies consistently show that roughly 40% of Google searches result in a click to an external website - the rest are 'zero-click searches' where users do not click to an external website.

Now, what's the click-through rate on ChatGPT? We don't have perfect data since ChatGPT doesn't publish CTR statistics.

But two independent studies came to the same conclusion: CTR in Google's AI Mode is roughly 5% - potentially lower. iPullrank observed a CTR of 3.8% to 5.4%. Semrush saw a CTR of 7% per session. With 2-3 searches per session, that a CTR of only 3% per search. And keep in mind, AI Mode shows sources a lot more prominently than ChatGPT!

For our calculations, we will assume that ChatGPT has a 5% CTR - substantially lower than Google's traditional 40% CTR.

Let's walk through the math:

If ChatGPT has a 5% CTR, and the average website received 24 clicks, there must have been about 480 searches (24 ÷ 0.05 = 480).

If Google has a 40% CTR, and the average website received 4,135 clicks, there must have been about 10,338 searches (4,135 ÷ 0.40 = 10,338)

That gives us a ratio: 10,338 Google searches to 480 ChatGPT searches. ChatGPT is roughly 4.6% the size of Google.

But what if ChatGPT's CTR is even lower? The table below shows how different CTR assumptions change the calculation:

Two methods, one answer

Using completely different approaches - direct usage data from OpenAI and a combination of referral traffic and CTR assumptions - we arrive at a consistent range: ChatGPT represents somewhere between 4% to 12% of Google's search volume.

This convergence suggests the estimate is fairly robust. ChatGPT is likely processing around 500 million to 1.7 billion searches per day, compared to Google's 14 billion.

In terms of search volume, Google is 8x to 22x bigger than ChatGPT.