[goosedragons]

Most of the sales of the "original" Skyrim were on Xbox 360 if sources are to be believed, Wikipedia has the 360 version as selling 13.7 million put of 23. And the PS3 version may have even outsold PC. Obviously anecdotal but that's where most of my friend base played it too.

[somenameforme]

I think it's fairly safe to say that those numbers are unlikely. One of the only real specific, and accurate, figures we can rely on is Bethesda in late 2011 saying they'd shipped (not sold) 10 million copies to retail (which excludes PC). In 2013 they stated that 20 million copies had been sold (which would include PC). The two notes I'd add here is that they never gave anymore shipped numbers, which means they probably never broke another meaningful benchmark on it, and that console titles (with very few exceptions) are overwhelmingly front loaded in sales.

I'm quite confident on the PC sales, because there's an oddly consistent little metric. For games that sell beyond a minimum amount, about 1 in 60 players tends to leave a written review. So total sales tends to be in the ballpark of written_reviews * 60. For Skyrim, that's 180,000 reviews or 10.8 million sales [1]. Linked because the game's been unlisted since the Special Edition came out. That metric also matches the mod count near perfectly, as well as Bethesda's sales announcements, and also their behaviors like trying to do things like create 'paid mods' (and the predictable backlash it entailed). So I'd estimate reasonable figures would be around 10 million on the PC, and a 2:1 360:PS3 ratio for the remainder. So you end up with somewhere around 10 million, 7 million, 4 million, with a variance probably in the range of something like 30%.

[1] - https://store.steampowered.com/app/72850/The_Elder_Scrolls_V...