This page compiles published data on OpenAI's GPT Store and custom GPTs, drawing on OpenAI's own disclosures (as catalogued by Wikipedia), OpenAI's 2025–2026 enterprise report (via secondary coverage), and third-party analyses from SEO.ai, SQ Magazine, and Master of Code.
The AI Behavior Index is the research arm of OneChat AI, an integrated multi-model AI platform. We compile and analyze data from primary research sources to make AI adoption and market trends more accessible to journalists, researchers, and decision-makers.
Why "3 million" and "159,000" are both right: 3 million+ is the number of custom GPTs created (most are private, unlisted, or for internal company use); ~159,000 is the number publicly listed in the GPT Store. They count different populations. Usage-share figures (12% of daily usage, 20% of enterprise messages) come from different studies with different denominators and should be read as approximate.
Methodology notes: creation counts are OpenAI disclosures; public-Store counts are third-party crawls and move over time. The 19x enterprise-growth figure is a year-to-date relative measure from OpenAI's enterprise report, shown here as an index (start of 2025 = 1x), not absolute volume. The category-distribution chart reflects the Store's 8-category structure and is illustrative of composition — OpenAI does not publish exact per-category GPT counts.
Sources used on this page:
- Wikipedia — "GPTs" (3M+ created by January 2024, OpenAI-sourced)
- SEO.ai — GPT Store Statistics & Facts (~159K public GPTs; 8 categories)
- SQ Magazine — ChatGPT Statistics (Custom GPTs ~12% of daily usage)
- Master of Code — ChatGPT Statistics in Companies (~20% of enterprise messages; BBVA 4,000+)
- Panto — OpenAI enterprise report summary (Projects & Custom GPTs ~19x growth in 2025)
Corrections or suggestions: research@aibehaviorindex.org