OpenAI’s mobile application has reached a new milestone as ChatGPT active users surpassed 1 billion monthly active users in May 2026.
According to estimates from research firm Sensor Tower, the platform achieved this milestone faster than any other application in history.
Growth Rate of ChatGPT Active Users
The mobile application reached the 1 billion threshold exactly three years after its initial launch. Consequently, the platform surpassed the growth pace previously set by major digital services, including Google Maps, TikTok, Instagram, and YouTube.
This rapid expansion highlights the ongoing competition in the artificial intelligence sector, where OpenAI competes directly with Anthropic’s Claude and X’s Grok.
Rising Competition from Claude and Grok
While OpenAI maintains a significant lead, competitors are beginning to gain measurable traction in the market. Specifically, Anthropic’s Claude reached 56 million monthly active users in the second quarter of 2026, representing a 640% year-on-year growth.
In comparison, the growth rate for ChatGPT active users stood at 62% during the same period. Furthermore, Elon Musk’s Grok recorded 50 million monthly active users on its mobile application.
Sensor Tower also analyzed user behavior in the United States during the first quarter of 2026. Notably, US users who installed Claude used OpenAI’s application 5% less in the month following installation compared to their average usage over the prior eight months.
“Claude’s growth could be driven by significant model advancements in the past year, or rising consumer sentiment after the announcement of OpenAI’s partnership with the Department of War in Q1 2026”
Sensor Tower
Historical Performance and API Usage
OpenAI has not released official statistics for 2026, but previous disclosures show substantial activity. In April, the company stated that it had reached 900 million weekly active users as of December 2025.
Meanwhile, developers using the platform generated an API usage rate exceeding 15 billion tokens per minute. These figures demonstrate the scale of the underlying infrastructure supporting the growing base of ChatGPT active users.
Financial Outlook and Market Expansion
The rapid growth of these platforms comes amid significant corporate developments in the technology sector. Anthropic filed for a United States initial public offering this week, and industry observers expect OpenAI to follow with its own filing soon.
As these companies transition to public markets, the metrics surrounding mobile apps and user engagement will remain critical indicators of market value.
