OpenAI ChatGPT Smashes 1 Billion Monthly Active Users Faster Than Any App in History

OpenAI's ChatGPT has crossed 1 billion global monthly active app users, becoming the fastest app ever to reach the milestone, according to estimates from market intelligence firm Sensor Tower. ChatGPT reached the mark in May, roughly three years after launch, surpassing the pace set by apps including Google Maps, TikTok, Instagram, and YouTube. The record comes amid growing competition between Anthropic and OpenAI for dominance in the rapidly expanding artificial intelligence market. But a rival is closing fast. Claude had 56 million global monthly active app users as of the second quarter to date, with year-over-year MAU growth of about 640% — significantly outpacing ChatGPT's 62%. U.S. ChatGPT users who installed Anthropic's Claude app in the first quarter of 2026 spent 5% less time on ChatGPT one month after installation. Anthropic confidentially filed for a U.S. IPO on Monday, while OpenAI is also preparing to file in the coming weeks.