ChatGPT Hits 1 Billion MAU in May, Claude Grows 640% Year-Over-Year

According to Sensor Tower, ChatGPT's mobile application reached 1 billion monthly active users globally in May 2026, becoming the fastest-growing consumer app in software history. The milestone was achieved in just three years since mobile launch, surpassing competitors like TikTok and Instagram, which took five to eight years to reach similar scale.

Claude, developed by Anthropic, is rapidly gaining ground with 56 million monthly active users and a year-over-year growth rate of 640%, far exceeding ChatGPT's 62% growth in the same period. Data shows that among U.S. users who installed Claude in Q1, ChatGPT's average daily usage time declined by 5% within one month.