ChatGPT App Tops 1 Billion Monthly Users
ChatGPT's mobile app crossed 1 billion monthly active users in May, per Sensor Tower — the fastest app ever to hit the mark, in about three years.
The ChatGPT mobile app has surpassed 1 billion monthly active users, according to a June 2 Reuters report citing market intelligence firm Sensor Tower. The app crossed the milestone in May, roughly three years after its initial launch.
The trajectory is unprecedented. For comparison, major platforms such as Google Maps, Chrome, YouTube, Meta's Messenger, and TikTok took between five and eight years to reach the 1 billion user threshold. The ChatGPT app achieved the feat in less than half that time, the fastest user growth any app has ever recorded, according to Sensor Tower.
From Five-to-Eight Years Down to Three
The rapid growth traces back to its rollout strategy. OpenAI launched the ChatGPT mobile app in May 2023, debuting on iOS in the United States before expanding to Android and international markets. At launch, the company noted that users had consistently expressed a desire to access the AI service on the go.
Three years post-launch, the app's monthly user base is growing at 62% year-over-year. Even with a user base nearing one billion, it managed to expand by over 60% in a single year. This growth stands out, particularly during a phase when expansion was expected to decelerate.
Historical benchmarks underscore the scale of this achievement. Mobile fixtures of the past decade, including Maps, Chrome, YouTube, Messenger, and TikTok, all required five to eight years to build a billion-user audience. The ChatGPT app met the same milestone in less than half the time, validating its status as the fastest-growing app in history.
Distinguishing Between Weekly and Monthly Active Users
However, the 1 billion milestone requires distinction from OpenAI's official figures. Sensor Tower's data tracks monthly active users (MAU) for the mobile app, whereas OpenAI focuses on weekly active users (WAU) across both web and mobile. In February 2026, OpenAI announced that ChatGPT surpassed 900 million WAU. This represented a 100 million user increase in just four months, up from 800 million in October 2025.
The mathematical difference between these metrics is substantial. App MAU counts unique users who launch the mobile application at least once in a 30-day period, whereas WAU includes web traffic and is restricted to a seven-day window. Because these methodologies differ, the figures are not directly comparable, and OpenAI itself does not publish monthly active user counts.
Revenue metrics offer another perspective on user engagement. Alongside its announcement of 900 million weekly active users, OpenAI disclosed that it has 50 million paying subscribers. Furthermore, third-party estimates from Appfigures indicate that cumulative consumer spending on the mobile app has surpassed $3 billion, with $2.5 billion of that total generated in 2025 alone.
Claude's Rapid Expansion and the Competitive Landscape
Competitors aiming for a share of this user base and revenue are also experiencing rapid growth. Sensor Tower data shows that Anthropic's Claude app reaches 56 million monthly active users, which is approximately one-eighteenth the scale of ChatGPT. However, Claude's mobile audience is expanding at a rate of 640% year-over-year, indicating a much steeper growth trajectory compared to ChatGPT's 62% rate.
Market share dynamics also reveal emerging vulnerabilities. In the United States, ChatGPT's share among major AI mobile apps slipped below 40% in recent quarterly snapshots, driven by intensifying competition from rivals like Google's Gemini and others. While OpenAI maintains its dominant lead, the battle for incremental market share is becoming increasingly competitive.
In response, OpenAI is reportedly moving to expand its consumer interface footprint. The company plans to integrate the ChatGPT app, its Codex programming tool, and a proprietary web browser into a desktop 'super app.' This consolidation aims to streamline the user experience while deepening engagement with developers and enterprise clients. With 1 billion monthly active users now on board, OpenAI's primary focus shifts from acquisition to retention — from adding monthly active users to holding them longer.
