Microsoft / Elyse Betters Picaro / ZDNET Follow ZDNET: Add us as a preferred source on Google. ZDNET's key takeaways Copilot has been the fastest-growing AI chatbot in recent months. Use of Google Gemini is also surging. ChatGPT still enjoys the greatest number of users. Do you use Microsoft Copilot, Google Gemini, or ChatGPT on your PC or mobile device? If so, you're in good company. The number of people who turn to these three AI-powered chatbots grew from March to June this year, according to the latest stats from analytics provider Comscore. Though all three of the major AIs enjoyed growth, one left the other two in the dust. For the three months tracked by Comscore, use of Microsoft Copilot surged by 175%, making it the fastest growing chatbot of all. In second place was Google Gemini with a gain of 68%, followed by OpenAI's ChatGPT with an increase of 18%. However, these stats measure only growth. Overall, ChatGPT still reigns supreme. Also: The best AI chatbots: ChatGPT, Copilot, and notable alternatives From March to June, the number of ChatGPT users reached 36.1 million on the desktop and 25.3 million on mobile. Next up, the number of Copilot users hit 23.1 million on the desktop and 8.8 million on mobile. As for Gemini, it saw 14.2 million users on mobile. ChatGPT scored big in one other important area. Based on Comscore's data, more than 85% of mobile users stay with one AI as a sign of deeper adoption rather than casual or trial use. Here, ChatGPT users showed the strongest loyalty, generally sticking with OpenAI's chatbot rather than exploring other options. In contrast, those who use Gemini and Copilot were more likely to check out other AIs, if only out of curiosity or broader use. (Disclosure: Ziff Davis, ZDNET's parent company, filed an April 2025 lawsuit against OpenAI, alleging it infringed Ziff Davis copyrights in training and operating its AI systems.) Still, Copilot's recent surge is significant. What's behind Microsoft's AI's hot growth, especially among mobile users? Also: Perplexity's $200 AI browser is free for students now - with more discounts to keep using it "Copilot's mobile growth comes mainly from Microsoft's ecosystem integration and productivity use cases," Smriti Sharma, SVP of Custom IQ for Comscore, told ZDNET. "The emphasis from Microsoft on its mobile-first approach fits well with lightweight productivity tasks." Sharma also shared insight into why ChatGPT's most recent growth was lower than that of the competition. "ChatGPT was the first mover, building a very large user base early on," Sharma explained. "That means its adoption curve is further along, and the growth now appears steadier. By contrast, Gemini and Copilot are still in a newer stage of adoption, so their growth rates are higher." The other AI tools that landed in the top five -- for either desktop or mobile use -- were AI-design assistant Canva, writing and editing helper Grammarly, AI marketing platform Octane AI, and AI voice changer Voicemod. Here, Canva grabbed 15.1 million users on the desktop and 7.6 million on mobile. Grammarly snagged 5.4 million on the desktop. Octane AI saw 8.3 million users on mobile. And Voicemod was used by 4.7 million people on the desktop. Comscore The data is based on Comscore's new AI tracking, which the company unveiled in May. The analysis looks at 117 AI tools across nine categories on PCs and mobile devices. From March to June, overall use of all the AIs tracked by Comscore rose by 5.3% on mobile devices, jumping from 69.7 million to 73.4 million people. Those numbers cover use of both mobile websites and mobile apps. On the desktop, AI use actually dropped by 11% over the three months tracked. Still, AI use remains slightly higher on the desktop with 78.4 million people vs. 73.4 million on mobile. Whatever the platform, the use of AI continues to surge. Also: 5 ways to fill the AI skills gap in your business "This latest trend shows AI is not just growing, it is exploding," Sharma said. "This evolution reflects how quickly consumers are embracing AI as a part of everyday life and how the top super tools like ChatGPT, Copilot, and Gemini are leading this charge with impressive mobile growth."