Meta’s Muse reaches 10.2 million U.S. downloads in 40 days, Sensor Tower estimates

Meta’s personal AI agent Muse has entered a small club: apps reaching 10 million U.S. downloads within their first 40 days. Sensor Tower estimates put Muse at 10.2 million, TechCrunch reported October 20. The new figures also show users returning at higher rates than rival AI apps, alongside a substantial advertising push from Meta.

From delegated errands to millions of installs

Meta introduced Muse on September 8, 2026, pitching an agent that carries out work rather than only answering questions. Its launch announcement described tasks such as sending email, booking travel and filling out forms. Meta says people can communicate with it through the standalone Muse app or directly in WhatsApp.

The company also describes an agent that keeps working after someone closes the app, returning when something changes or approval is needed. Sending an email or making a purchase are among the actions Meta says require permission. That is the product proposition behind the download surge—not simply another place to chat.

Sensor Tower puts total downloads at 10.9 million in the first 40 days, with the U.S. accounting for 10.2 million. Its senior insights analyst Kara Lee told TechCrunch that only 11 other apps had crossed the U.S. threshold that quickly. The most recent was Meta’s Threads in July 2023; most of the others were mobile games.

Meta puts more of its advertising behind Muse

The rollout has had help from Meta’s existing services, where the company has promoted Muse. Paid advertising is another substantial part of the effort. Sensor Tower estimates that Muse accounts for 39% of Meta’s total advertising spending in October, up from 23% in September.

Muse has become a much more visible advertiser. Sensor Tower ranks it as the 21st-largest brand in the U.S. by advertising impressions this month, compared with 73rd in September. Those figures describe the scale of promotion; they do not measure whether someone who installs the app keeps using it.

Returning users add weight to the download milestone

Retention tracks users returning after installation, rather than counting new downloads. The comparison is with the average for ChatGPT, Claude and Grok, not an individual breakdown for each rival.

Active use has also grown. Muse reached 2.5 million daily active users for the first time on October 16, a 15% week-over-week increase, according to TechCrunch. This captures people using the app on a particular day rather than everyone who has downloaded it.

The first-40-day U.S. download comparison is striking, too. Sensor Tower estimates put ChatGPT at 3.7 million downloads over its equivalent launch window, Grok at 500,000 and Claude at 200,000. These are comparisons with each app’s own debut, not their current download totals or current audience sizes.

The geography changes the result. ChatGPT reached roughly 15 million downloads globally in its first 40 days, ahead of Muse’s total, but had a wider international release. Muse remains available only in the U.S. and Canada. For now, Muse’s retention evidence extends to two weeks—not yet a verdict on whether its rapid adoption becomes a lasting habit.