According to estimates from market intelligence company Sensor Tower, the number of global monthly active users of OpenAI's ChatGPT has exceeded 1 billion, becoming the fastest application in history to reach this milestone. The record comes as Anthropic and OpenAI compete for dominance in the rapidly expanding artificial intelligence market.
Sensor Tower said that ChatGPT reached 1 billion monthly active users in May, only about three years after its launch, surpassing the previous growth records set by applications such as Google Maps, TikTok, Instagram and YouTube.
The agency said that among U.S. ChatGPT users who installed Anthropic’s Claude app in the first quarter of 2026, one month after installation, their ChatGPT usage time decreased by 5% compared with the average usage time in the previous eight months.
Anthropic secretly submitted an initial public offering (IPO) application on Monday; Reuters previously reported that OpenAI also plans to submit an IPO application in the next few weeks.
According to Sensor Tower data, as of the second quarter, Claude's global monthly active users (MAU) have reached 56 million, and its year-on-year growth rate of approximately 640% far exceeds ChatGPT's 62% growth rate.