**[ChatGPT Monthly Active Users Surpass 1 Billion, Setting Record for Fastest Growth in History, While Claude Sees a 6.4x Year-on-Year Surge, Beginning to Divert Users]** According to monitoring by Dongcha Beating, OpenAI's ChatGPT mobile app surpassed 1 billion global monthly active users (MAU) in May 2026, becoming the fastest-growing mobile application in the history of software. Based on estimates from Sensor Tower, it took ChatGPT only three years from its mobile launch to reach 1 billion MAUs, breaking the growth trajectory of mainstream global applications. In comparison, TikTok, Instagram, and Google Maps took between 5 to 8 years to achieve the same user scale. Although these estimates are not officially audited disclosures from OpenAI, they have been regarded by the market as key indicators for assessing the adoption rate of consumer-grade AI. Despite ChatGPT maintaining an absolute advantage in scale, Anthropic's Claude is rapidly diverting user time. In the second quarter of 2026, Claude's global monthly active users reached 56 million, with a staggering year-on-year growth rate of 640%, far exceeding ChatGPT's 62% growth rate during the same period. Sensor Tower tracking indicates that the direct competition for user time between the two applications is already evident in the data. Among U.S. users who installed Claude in the first quarter of 2026, the average usage time of ChatGPT per person decreased by 5% within just one month. [Original Link]