Ahrefs calls it AI adjusted volume, a number built to estimate how often people ask AI platforms about a topic. It starts with a Google search volume figure, multiplied by a ratio that differs by AI platform. Ahrefs published the method behind the number on August 17, and the option to see the plain Google figure sitting underneath it is available until August 31.
How does Ahrefs calculate AI adjusted volume?
Ahrefs identifies each prompt’s parent keyword and looks up that keyword’s Google search volume, then applies a platform-specific ratio to estimate demand on that AI platform. The company states the ratios “are derived from Ahrefs’ aggregated website traffic data coming from different AI platforms relative to organic traffic from Google.” Ahrefs frames the result as directional, not measured: “So while our estimates are not derived from user query data, they can be used directionally”.
Why start from Google search volume at all?
Ahrefs’ explanation is about market structure. The post says “there’s no significant, reliable source of data about how people prompt AI for answers.” It adds that no major AI platform publishes what people actually ask: “Until today, no major AI platform (such as ChatGPT, Perplexity, Gemini, Claude, etc.) shares their query data with anyone. None of them publish what users are actually asking AI, or how often.” Google is different in kind, Ahrefs argues, because “Google still owns over 90% of the search market share. With AI, this is significantly less concentrated, across many more providers.” Google also shares data through “Google Keyword Planner, Google Search Console, Google Trends, etc.” And because “Almost all search is made through the browser,” Ahrefs says the query samples that opt-in panels and clickstream providers collect are more reliable for Google searches than for AI prompts. People can use AI “through a browser, desktop app, API, through third party AI platforms, messenger chatbots, etc.” Ahrefs states that “Most of these methods have no way for a third party tool to capture real user prompts made in AI.”
What Ahrefs says other AI-visibility tools do instead
The post frames the wider field as choosing among four approaches, in its own words:
- “Extrapolate from a much smaller set of clickstream data from opt-in browser panels.”
- “Generate prompts based on algorithmically created variations of seed keywords—and assign them estimated volumes without any direct measurement at all.”
- “Like Ahrefs, derive estimates from traditional search volume estimations.”
- “Avoid providing estimates entirely”
That is Ahrefs’ own characterization of competing approaches, not an independent survey of what any named tool does. Ahrefs places its own method in the third bucket.
What AI adjusted volume can and cannot tell you
The post states outright: “AI Adjusted volume is not helpful for:”
- “Deriving AEO KPI numbers”
- “Estimating AI search-only addressable market size”
- “Measuring how many people saw your brand mentioned in a specific AI response”
It also lists, in the same post, what the number is helpful for:
- “Benchmarking brand visibility and AI Share of Voice (SOV) against competitors”
- “Identifying which topics are more top-of-mind for your audience”
- “Comparing which AI Platforms can drive more brand impressions for your niche”
- “Determining which cited pages get more eyeballs in relevant answers”
What Ahrefs’ CMO said about “prompt search volume”
Tim Soulo, CMO at Ahrefs, posted on X. The only verified rendering of that post surfaced in Search Engine Roundtable’s August 27 recap, and it cuts off mid-sentence:
There is no such thing as “prompt search volume.” If you’re paying for it, you’re wasting your money. I’ve actually looked at a bunch of data samples from clickstream providers who track what people type into ChatGPT. Can you guess what I saw? Multi-sentence paragraphs […]
The blog post never calls its own number “prompt search volume.” It calls it “AI adjusted volume,” and treats it as an estimate from the first paragraph to the last. The two statements are consistent: one documents a formula and its limits, the other rejects a label that formula does not use.
The pattern behind the number
A number that does not mean what its name suggests is a recurring subject here. A Growth Memo study published August 24 reported that most vendor-authored listicles gained estimated traffic while listicle share at position one fell; our reading found the two figures come from the same author and the same window but measure different things, and that the study calls itself observational. Google’s Branded Searches help page was rewritten with no changelog or announcement: the metric’s default lookback window shrank and Performance Max dropped off the supported list. AI adjusted volume belongs on that list. The name points at AI search demand; the formula is a Google search volume multiplied by a platform ratio.
What to do before August 31
Brand Radar currently carries a temporary toggle. Ahrefs says: “we’ve temporarily added an option in Brand Radar to switch back to plain Google search volume for comparison. That option will be available until August 31, 2026, after which reports will use AI adjusted volume only.” Anyone tracking AI adjusted volume for a brand or a set of competitors has until August 31 to pull both numbers side by side for the topics that matter, and to note the gap between them, before only the derived figure remains visible in the report. After that, use the metric for what Ahrefs itself says it is good for: benchmarking share of voice against competitors, ranking topics by attention, and comparing platforms and cited pages against each other. Do not build an AEO KPI, an AI search-only market-size estimate, or a per-response view count on top of it. Ahrefs itself lists all three as things the number is not helpful for.