For 17 years, YouTube has ruled digital video.

• More than two-thirds of the US population and more than three-quarters of internet users visited YouTube monthly in 2021, we forecast.
• On a monthly basis, more people viewed video on YouTube last year than used Facebook (225.8 million compared with 179.1 million, respectively).
• There were almost as many monthly YouTube viewers as monthly TV viewers (245.7 million) last year.

But the increase in video viewing on other social platforms—primarily TikTok—is eating into YouTube’s dominance. With more venues displaying videos, user attention is starting to become divided. The same holds true for creator videos: YouTube, once the 800-pound gorilla, is increasingly fighting to keep its most popular creators from going elsewhere.

The growth of TikTok doesn’t yet amount to a full changing of the guard when it comes to social video winners and losers. YouTube is still ahead of TikTok in total users and in every age group we forecast.

• YouTube will have well over twice as many monthly users as TikTok this year (230.6 million compared with 90.6 million, respectively).
• More than half of children ages 0 to 11, essentially Generation Alpha, will use YouTube this year, compared with just 4.6% on TikTok.
• By generation, YouTube will have nearly double the penetration of TikTok among millennials this year, almost four times as many Gen Xers, and about eight times the penetration among baby boomers.

However, if we drill down into a few key age groups, TikTok is gaining fast.

• Among US teens ages 12 to 17, 87.6% will use YouTube monthly this year, while 65.3% will use TikTok, according to our forecasts. YouTube’s penetration is reaching a ceiling, while TikTok’s is still rising fast; YouTube will rise just 1.5 percentage points this year compared with 2020, while TikTok will be up more than 13 points (from 51.7%).
• In the 18-to-24 group, the usage gap will be even smaller than among teens this year: 85.4% will be on YouTube monthly and 73.9% will be on TikTok.
• By 2025, there will be 24.2 million US TikTok users ages 18 to 24 and 26.6 million US YouTube users.