What Roblox shows you
Your Roblox profile shows account creation date, place visits, badges, and favourites. None of that is playtime. Individual experiences may display their own session or progression timers, and some have leaderboards based on time in that experience, but those are built by the creators rather than by Roblox.
There is no platform-level "hours played" figure, either per experience or overall.
Why parents and players both want this
Two different groups search for this. Players want to know how much time a favourite experience has taken. Parents want a factual answer about how much time is going into Roblox overall, ideally without relying on the child self-reporting.
Roblox's own parental controls focus on chat, spending, and content settings rather than producing a running total of time played on a PC. Windows Family Safety can restrict and report screen time for an account, which is a policy tool rather than a playtime log.
Tracking the Roblox client on Windows
PlayCounter records how long the Roblox client runs. Whichever experiences are played inside it, the session time is captured and accumulates into a total with a session count and a dated history, so you can see both the overall figure and the pattern across days.
The honest limitation is the same one that applies to browsers and cloud gaming clients: Roblox runs many different experiences inside one client process, so a tracker that watches processes records "Roblox" rather than the individual experience within it. If you need per-experience numbers, that has to come from the experience itself.
For the total-time question - the one most people are actually asking - client-level tracking answers it accurately, locally, and without any account.