Terraria was literally the first video game I ever played, so I was very young, the lines are hazy, and I SOMEHOW SPENT OVER 450 HOURS ON A CHARACTER THAT DIDN'T EVEN BEAT A MECHANICAL BOSS? I originally played it on the PS4, but recently, it's been corrupting data (characters in this case) for lots of my games (not just Terraria) so that incentivised me to switch to PC. Also, when playing with my sibling, this was on PC - so we got it working using split screen and the PS4 controllers. However, the steam stat included both windows of the game, meaning play time doubled when I played with her.
Due to the multitude of reasons above, it's nowhere near exact, but here it is anyway:
PS4: Roughly 700-800 Hours
PC: Roughly 100 Hours
Mobile: Just over 2 Hours (I got it very recently)
Total: Approximately 800-900 Hours