For the past few years, the artificial intelligence (AI) assistant market has largely belonged to OpenAI’s ChatGPT. It defined the category, set the pace of adoption and built a user base that no rival could match.
That picture is becoming more complicated.
The lead remains substantial, but the gap is narrowing in ways that matter.
ChatGPT crosses one billion users
India has played a significant role in that achievement and continues to. ChatGPT had 330 million unique monthly users in India in May 2026, up from 297 million in December 2025, making it one of the platform’s largest markets. This suggests that roughly one in three ChatGPT users globally is Indian, a proportion that underscores just how central the Indian market has become to the platform’s global story.
A billion at the top, but the field is catching up
The billion-user milestone is a genuine achievement, but the more instructive part of Sensor Tower’s data is what is happening below it. Across the 25 markets covered in the report, ChatGPT leads with 1.11 billion monthly users as of May 2026, up from 1.05 billion in December 2025.
Google Gemini, meanwhile, moved from 533 million to 662 million monthly users over the same period, a jump of 129 million users in five months. And Claude, which had 60.2 million monthly users in December 2025, surged to 245 million by May 2026, a roughly fourfold increase
The competitive dynamic looks similar in India. ChatGPT leads with 330 million monthly users. But Gemini is not far behind at 229 million, a gap that is considerably narrower in India than it is at the global level. Claude has climbed to 72.3 million monthly active users in India by May 2026, up from 13.3 million in December 2025.
What those user numbers also reflect is an extraordinary level of engagement. As per preliminary estimates by Sensor Tower, Indian users are projected to spend 5.82 billion hours on generative AI apps in the first half of 2026, up from 1.66 billion hours in the same period a year earlier. Total sessions in India is also projected to reach 168 billion in the first half of CY 2026, compared to 47 billion in the first half of CY 2025.
Market share: Below 50 per cent for the first time
User numbers tell you who is winning. Market share tells you by how much, and by that measure, the story of the past eighteen months is one of steady erosion at the top. ChatGPT’s share of the global AI assistant market fell below 50 per cent for the first time in March 2026 and stood at 46.4 per cent by May, down from 52.8 per cent in December 2025 and 65.3 per cent in December 2024. The platform that once commanded nearly two-thirds of the market now holds less than half.
The ground it has lost has gone primarily to two players. Google Gemini held 27.7 per cent of the global market by May 2026, up from 18.2 per cent in December 2024. Claude held 10.3 per cent globally in May, up from just 3 per cent in December 2025. The remaining share is distributed across Grok at 3.3 per cent, DeepSeek at 3.2 per cent, Perplexity at 2.8 per cent, Meta AI at 2.5 per cent, and Microsoft Copilot at 1.6 per cent.
In India, the market share picture has its own contours. ChatGPT held 45.6 per cent in May 2026, down from 59.1 per cent in December 2024. Google Gemini held 31.6 per cent, meaningfully higher than its global share of 27.7 per cent, a difference that reflects both Android’s dominance in India and Google’s deep ecosystem integration in the market. Claude held 10 per cent in India by May 2026, up from 2.2 per cent in December 2025. Perplexity at 3.7 per cent and Meta AI at 3.2 per cent are the other notable players in the Indian market.
The direction of travel across both the global and Indian numbers is consistent: ChatGPT’s share is declining, Gemini’s is rising, and Claude’s has moved from marginal to meaningful in a matter of months.
Why the gaps are closing
Several forces are working simultaneously to reshape the market, and understanding them matters for reading where things go next.
Gemini’s growth in India and globally is difficult to assess without accounting for its structural advantage. Google Gemini is deeply integrated across Search, Gmail, Google Docs, and the Android operating system itself, and in India, where Android commands over 90 per cent of the smartphone market (Counterpoint research data), that gives Gemini a distribution reach that no competitor can match organically.
The more revealing dynamic is how willing users of this app segment have proven to switch. According to Sensor Tower, in the US, ChatGPT uninstalls surged to roughly 200 per cent above the app’s average during the week of March 9 to 15, following OpenAI’s agreement to work with the US Department of War.
Many of those users appear to have moved to Claude, which recorded more daily downloads than ChatGPT from March 1 to 5, 2026. ChatGPT has led on daily downloads every day since, but the margin has remained considerably narrower than it was before March, suggesting that a portion of that switched audience stayed switched.
The introduction of advertisements on ChatGPT in the US during this period added another layer of friction. Sensor Tower’s data shows ChatGPT’s churn rate moving from 12.7 per cent in January to 14.5 per cent in April, a period that coincided with the arrival of ads on the platform.
Claude’s five-month surge
Claude’s growth is worth examining. Antropic’s AI platform went from 60.2 million to 245 million monthly users worldwide in five months. In India, Claude went from 13.3 million monthly users in December 2025 to 72.3 million in May 2026, with its market share climbing from 2.2 per cent to 10 per cent over the same period.
What makes the trajectory more significant than a one-time controversy-driven spike is what happened to retention in the months that followed. Sensor Tower’s data shows Claude’s share of churned users in the US declining rapidly since March, bringing it closer to ChatGPT’s retention levels. The platform is not just attracting new users; it is keeping them.
The broader AI app market
Stepping back from the assistant race to the AI app market as a whole, Sensor Tower’s report shows a market that is maturing in its acquisition phase but accelerating in engagement. Global AI app downloads are projected to reach 2.3 billion in the first half of CY 2026, up 7 per cent half-over-half. That is a significant deceleration from the 26 per cent growth recorded in the second half of CY 2025 and the 71 per cent seen in the first half of CY 2025.
In India, downloads are projected to reach 348 million in the first half of CY 2026, a pullback from the 369 million recorded in the second half of CY 2025. That decline, however, needs context. The second half of CY 2025 was itself an outlier, growing significantly from the 217 million downloads seen in the first half of the calendar year, a surge that coincided with an aggressive wave of promotional activity from OpenAI, Google, Perplexity, and others, including free access tiers, student plans, and telecom partnerships. The first half of CY 2026 looks softer primarily because the second half of CY 2025 was unusually strong, and the moderation likely reflects the normalisation of that promotional push.
Asia as a region, recorded its first decline in AI app downloads in Q1 CY 2026, with downloads falling 3.3 per cent against the previous quarter to 462 million, after 13 consecutive quarters of uninterrupted growth. Both India and China have pulled back from prior download peaks, with India’s reached in October 2025 and China’s in March 2025.
AI is also spreading well beyond dedicated assistant apps. The number of apps mentioning AI, machine learning, or large language model on their store pages is on track to approach an all-time high in the first half of CY 2026, with downloads for such apps up 25 per cent year-on-year and 173 per cent compared with the first half of CY 2023.
Health and wellness, utilities, jobs and education, financial services, and shopping each grew more than 40 per cent year-on-year as developers across categories integrated AI features, according to the Sensor Tower report.
The Q1 CY 2026 download rankings in India also offer a telling detail. While the global top five by downloads features ChatGPT, Google Gemini, Grok, Claude, and a scheduling assistant called Dola: Asisten AI Cerdas, India’s list includes Vidix-AI Photo Video Generator, a media generation tool, as the fourth most downloaded AI app. Its presence points to an Indian user base drawn to AI for visual content creation.
The list includes ChatGPT, Google Gemini and Meta AI as the top three most downloaded AI app in India, with Grok rounding up the top five.
Revenue from AI platforms
Downloads are moderating, but revenue is not. Global in-app purchase revenue from AI apps is projected to surpass $4.25 billion in the first half of CY 2026, up 36 per cent half-over-half. The divergence between 7 per cent download growth and 36 per cent revenue growth tells a clear story: the users who are staying are paying. ChatGPT alone is projected to contribute more than $2.5 billion of that global total. Across all apps mentioning AI terms, the projected total rose to $12 billion in the first half of CY 2026, up 61 per cent year-on-year.
Against that backdrop, India’s revenue position is an uncomfortable data point in the report. With 330 million ChatGPT users and 229 million Gemini users monthly, India is among the world’s largest AI app markets by user count. The projected engagement numbers, 5.82 billion hours spent and 168 billion sessions on generative AI apps in the first half of 2026 alone, are not those of a casual market. However, India’s projected in-app purchase revenue from AI apps in the first half of CY 2026 is $38 million, against a global total of $4.25 billion. That is less than 1 per cent of global revenue from one of the world’s most active user bases.
India’s app economy has been a volume market rather than a value market, with users resistant to subscription pricing and in-app purchases. According to Sensor Tower’s India Mobile App Market report that was released earlier this year, India remains the world’s largest app download market by a wide margin, yet does not rank among the top 20 markets globally in app revenue.
However, there is an upward trend. Annual IAP revenue in India has risen from $520 million in CY 2021 to over $1 billion in CY 2025 and is projected to reach $1.25 billion in CY 2026, according to Sensor Tower data cited by TechCrunch.
In a statement to TechCrunch, Donny Kristianto, principal market insights manager at Sensor Tower, said that India’s app market has matured on the download side, but monetisation is strengthening as usage deepens and digital payment habits become more embedded.
What the numbers suggest
ChatGPT remains the clear market leader. Reaching one billion monthly users in just three years is a milestone unmatched by any consumer platform in history.
Yet the competitive landscape is changing.
Gemini is leveraging Google’s ecosystem advantages to gain share. Claude has emerged as the fastest-growing major AI assistant. New entrants continue to capture niche segments.
The AI assistant market is no longer defined solely by OpenAI.
ChatGPT still sits at the top, but for the first time since the generative AI boom began, the lead looks increasingly contestable.
