In January 2020, WhatsApp became the second non-Google app to pass 5 billion Google Play installs.
The milestone referred to Google Play’s Android installation counter, whose highest public bracket at the time was more than 5 billion. WhatsApp joined Facebook, which had reached the same threshold earlier. Most other apps in that bracket were Google products commonly preinstalled on Android phones, such as YouTube, Chrome, Gmail, and Google Play Services.
This was an installs milestone, not a count of unique people currently using WhatsApp. Android users can install the app more than once, and preinstalled or bundled software can accumulate large totals through device distribution. Google Play also reports broad thresholds rather than an exact public download count.
WhatsApp had been available on Android since 2010 and had grown into one of the world’s most widely used messaging services. Its international reach, phone-number-based registration, and availability across many Android devices helped drive the enormous total.