# ChatGPT Reaches One Billion Monthly App Users > Source: > Published: 2026-06-12 06:51:20.496659+00:00 # ChatGPT Reaches One Billion Monthly App Users OpenAI's **ChatGPT** reached **1 billion** monthly active app users in May, according to market-intelligence firm **Sensor Tower**, which called it the fastest app ever to hit the milestone roughly 3 years after launch (reporting via Reuters and CNBC). Sensor Tower's data, cited by Reuters, also shows **Claude** had about **56 million** global monthly app users in Q2-to-date and posted roughly **640%** year-over-year MAU growth versus **ChatGPT**'s **62%**. Reuters reported that U.S. users who installed Anthropic's Claude spent about **5%** less time on ChatGPT one month after installation. CNBC notes the milestone comes amid rising public unease about AI's ethical and environmental impacts and public protests; CNBC reports OpenAI did not respond to its requests for comment. Reuters also reported filings and IPO activity involving Anthropic and OpenAI. ### What happened OpenAI's **ChatGPT** reached **1 billion** monthly active app users in May, based on estimates from market-intelligence firm **Sensor Tower**, Reuters and CNBC report. Sensor Tower described **ChatGPT** as the fastest app to reach the **1 billion** MAU mark, achieving the milestone roughly three years after launch, per Reuters. Reuters also cites Sensor Tower figures showing **Claude** at **56 million** global monthly active app users in the second quarter to date and a year-over-year MAU increase of about **640%**, compared with **ChatGPT**'s **62%** growth. Reuters reports that U.S. users who installed Anthropic's **Claude** in Q1 spent about **5%** less time on **ChatGPT** one month after installation. CNBC reports the milestone comes as public sentiment about AI has cooled, noting protests and ethical and environmental concerns; CNBC reports OpenAI did not respond to its request for comment. ### Editorial analysis - technical context Industry-pattern observations: MAUs reported by third-party app-intelligence firms like **Sensor Tower** measure app installs and client-side activity; they do not directly equate to server-side API usage, enterprise deployments, or cross-platform web traffic. For engineers and product teams, third-party MAU metrics are useful for comparing consumer app reach but are an imperfect proxy for backend load, API call volume, or enterprise adoption. ### Industry context Industry observers note that the data points on **Claude**'s rapid percentage growth and the observed falloff in **ChatGPT** engagement among some U.S. users after installing **Claude** illustrate intensifying consumer competition, per Reuters' reporting of Sensor Tower. At the same time, CNBC's reporting on souring public sentiment underscores growing scrutiny from civil-society groups and media, which can affect regulatory attention and public-facing product decisions. ### What to watch - •Retention and engagement trends in third-party and publisher metrics versus app-store MAUs - •Differences between app MAUs and API/backend usage that drive infrastructure costs - •Regulatory and public-pressure signals tied to protests and ethical/environmental coverage - •Company filings and IPO activity reported by Reuters for Anthropic and OpenAI For practitioners: monitor both consumer-facing metrics (app MAUs) and backend telemetry (API call volumes, latencies, cost per inference). Third-party app-intelligence milestones are meaningful for market signal and competitive benchmarking, but they should be combined with platform-level telemetry when assessing operational impact. ## Scoring Rationale A 1-billion MAU milestone is a notable product adoption signal with competitive and market-sizing implications for AI practitioners; Sensor Tower data on Claude's 640% MAU growth and session-time cannibalization adds substantive competitive context. Scored in the Notable range -- significant consumer reach story but primarily a market metric rather than a new model or technical breakthrough. Practice interview problems based on real data 1,500+ SQL & Python problems across 15 industry datasets — the exact type of data you work with. [Try 250 free problems](/problems)