ChatGPT reaches 1 billion monthly users, fastest app to hit milestone

OpenAI’s ChatGPT has surpassed 1 billion monthly active users worldwide, making it the fastest application to ever reach that milestone, according to estimates from market intelligence firm Sensor Tower.

The achievement comes amid intensifying rivalry between Anthropic and OpenAI as both compete for leadership in the rapidly expanding artificial intelligence sector, Caliber.Az reports, citing Reuters.

Sensor Tower said ChatGPT reached 1 billion monthly active users in May, approximately three years after its launch, outpacing major platforms such as Google Maps, TikTok, Instagram, and YouTube in terms of speed to the milestone.

The firm also noted shifts in user behaviour, stating that US users who installed Anthropic’s Claude app in Q1 2026 spent 5% less time on ChatGPT one month after installation compared with their average usage over the previous eight months.

Separately, Anthropic confidentially filed for a US initial public offering on Monday, while Reuters has reported that OpenAI is also preparing to submit its own IPO filing in the coming weeks.

Sensor Tower data further showed that as of the second quarter, Claude had about 56 million monthly active users globally. However, its year-over-year growth rate of approximately 640% significantly outpaced ChatGPT’s 62% expansion, highlighting the rapid expansion of competition in the AI app market.

By Bakhtiyar Abbasov