ChatGPT Reaches 1 Billion Monthly Users in Record Time

Research company Sensor Tower estimates that OpenAI’s ChatGPT crossed 1 billion monthly active users (MAUs) on its app in May 2026. This way, ChatGPT became the fastest tech product in history to reach the number.

In its State of Mobile Report 2026, Sensor Tower found that ChatGPT beat the pace set by other popular apps including Google Maps, TikTok, Instagram and YouTube in hitting the 1 billion threshold, a milestone coming three years after launch. The number represents a win for OpenAI in the battle for AI chatbot supremacy, with ChatGPT competing with the likes of Anthropic’s Claude and X’s Grok.

In April, OpenAI revealed it hit 900 million weekly active users as of December 2025, and API usage is more than 15 billion tokens per minute. However, it has not revealed official statistics for 2026. Sensor Tower noted Claude is beginning to gain traction. As of the second quarter of 2026, Anthropic’s offering hit 56 million MAUs for its app, representing growth of 640% year-on-year. This compared to 62% growth for ChatGPT.

Sensor Tower also noted that US users of ChatGPT who installed Claude in the first three months of 2026 used the former app 5% less a month after installation, compared to the average use in 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 1Q26,” Sensor Tower stated.