400M users and counting: ChatGPT’s growth shows no signs of slowing

OpenAI’s flagship AI chatbot, ChatGPT, has seen significant user growth, doubling its weekly active users to 400 million in under six months, as reported by VC firm Andreessen Horowitz (A16z). This growth follows its initial rise from 100 million weekly active users in November 2023 to 200 million in August 2024.

After its release in November 2022 as a research preview, ChatGPT quickly reached 100 million monthly active users within just two months. By November 2023, it achieved 100 million weekly active users, which escalated to 300 million by December 2024, and reached 400 million by February 2025.

A16z notes that early consumer interest in ChatGPT was primarily driven by novelty, as users explored the app without a clear understanding of its practical applications. However, recent growth can be attributed to the launch of new models and features, specifically the introduction of GPT-4o, which incorporates multimodal capabilities. Following this launch, there was a notable surge in usage from April through May 2024.

Further enhancements, including the Advanced Voice Mode and the o1 model series, contributed to increased user engagement, particularly from July to August and September to October 2024, respectively.

On mobile platforms, ChatGPT’s user base has been consistently increasing, with a month-over-month growth of 5% to 15%. Currently, 175 million of its total 400 million weekly active users access the app via mobile devices.

The report also highlights competition from rivals such as DeepSeek, which attained the No. 2 position globally within ten days of its launch and captured 15% of ChatGPT’s mobile user base by February 2025. Despite higher engagement rates among DeepSeek users compared to those using Perplexity and Claude, it still falls short of ChatGPT’s user engagement levels.

Additional insights from the market analysis include recommendations for AI development tools, rankings of the leading AI applications by category and revenue, as well as lists of the top generative AI applications across mobile and web platforms. ChatGPT ranks first in unique monthly visits on the web and in monthly active users on mobile, as indicated by data from Similarweb.

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