Short answer
Prompt volume is an estimate of how often people ask AI assistants such as ChatGPT or Gemini about a topic or question. It is the AI equivalent of keyword search volume. Because AI companies do not publish this data, prompt volume is modeled from search data, panels and tool usage, so treat it as a guide to relative demand, not an exact count.
How to use it well:
- Pick questions, not keywords. People write full questions to AI, often with context like budget, city or industry.
- Use it to rank topics, not to forecast traffic. A topic with high prompt volume and no brand named in answers is an opportunity.
- Cross-check with search data. Questions with high Google search volume usually get asked to AI as well.