eMarketer: in the US, TikTok is expected to grow 21.9% YoY to 45.4M MAU in 2020, down from 97.5% growth in its breakout year of 2019
More than 20% of social users will use TikTok this year … After nearly doubling its US user base last year, growth for TikTok will slow in the coming years …
Context & Ripple Effects
eMarketer's 2020 forecast lands one year after TikTok's breakout: US monthly users nearly doubled in 2019, and the firm now expects growth to cool to 21.9% — still adding millions of users, but at less than a quarter of the prior year's pace. The same analyst shop had just projected that Snapchat's US user base would decline 2.8% to 77.5M in 2019, making TikTok the clear share-taker in a flattening US social market.
The deceleration arrives just as TikTok turns to monetization: it reportedly expected around $500M in US revenue in 2020, up from a few hundred million worldwide the year before. Subsequent coverage shows the US base kept climbing past the 45.4M projection — 100M+ by 2021 and 145M by end-2024 — while the growth engine shifted abroad, with ByteDance crediting TikTok's global expansion for its ~$186B 2025 revenue outlook and Europe passing 200M monthly users.
First-order effects
- TikTok's US user base keeps growing in 2020, but the 21.9% pace means the easy-doubling phase is over and the platform must convert its 45.4M US users into ad revenue — the same year it targeted $500M in US sales.
- Snapchat, which eMarketer already had shrinking in the US, now faces a TikTok that is adding users at a moment Snap is losing them, sharpening the fight for the under-24 demographic TikTok later claimed as 59% of its base.
Second-order effects
- US advertisers get a maturing domestic audience earlier than expected, pushing TikTok to build out new ad formats for the pitch decks it would later take to US buyers rather than rely on raw user growth to sell inventory.
- With US growth slowing, ByteDance's expansion calculus tilts toward international markets — the pattern later visible in Europe's climb from 175M to 200M+ users and in global revenue, not US headcount, driving ByteDance's ~$186B 2025 outlook.
Third-order effects
- The 2020 slowdown call foreshadows a structural pattern for hypergrowth social platforms: user growth decelerates in the US within a couple of years of breakout, and the business shifts from land-grab to monetization depth plus overseas expansion — the arc that carried TikTok from a 45.4M-user US forecast to 145M US users but a growth story increasingly told through Europe and global ad revenue.
The trend: Breakout social apps decelerate in the US within two years and pivot to monetizing the base while sourcing growth internationally — a trajectory TikTok's 2020 forecast marked and its 2025 global numbers confirmed.