January 2020 MAU
According to RTrack analytics, Roblox hit 119M+ MAU in January of 2020. In December, RTrack data showed a MAU of 113M+ users in the 30 days preceding December 31st 2019. Data recorded by RTrack in January, measuring the 30 days before January 31st, shows a monthly active user count of roughly 119,355,918 user accounts, an increase of more than 6 million on the previous month. Shown below is data from an August 2019 Business Insider article  and RTrack’s most recent data.
This hints at strong user growth for Roblox in terms of monthly active users, with a large jump in players. There also evidence of improved retention of users; January’s data shows that 8.3% of the randomly sampled group (totalling 80,200 users) were online in the past month, compared with 8.24% of users in December 2019 (same sample size).
RTrack’s value for January 2020 MAU is an estimate based on a randomly selected sample of 80,200 Roblox accounts, of which 6,691 were found to have been online in the past 31 days. At the time of calculating, total Roblox acccounts were estimated to total 1.43 billion, using the percentage of the sample online (8.3%), total monthly active users were estimated to be between 118 and 119 million. This process was allowed to run four times with a different sample group, with MAU falling between 118 and 119 million each time.
RTrack does not make any claims as to the validity or accuracy of the values shown in this blog post, and is not associated with Roblox Corp. These values are not official Roblox figures and were not released by Roblox Corp.
 “Roblox has eclipsed Minecraft with 100 million users — highlighting the popularity of ‘digital hangouts'” As of 12th January 2020: https://www.businessinsider.com/roblox-user-growth-surpasses-minecraft-2019-8?r=US&IR=T