Why is Miley constantly used as a shady poll option on this forum.
Beyonce is definitely musically bigger worldwide in terms of record sales. Miley's sold around ~7,000,000 albums outside the US, compared to Beyonce with like 13(?) million. I'm not sure. I just know Beyonce's sold more.
In terms of film, Miley's 5 films have grossed $307,541,080 outside the US collectively, compared to Beyonce's $220,297,415 outside the US with 6 films.
Miley's never had a tour gross >$100,000,000, but both the Wonderworld Tour and Gypsy Heart Tour (a South American, Australian and Asian tour) both made more on average per night ($1.1 million and $1.2 million respectively, compared to about $1 million) than the I Am World Tour. I'd also remind you that it was Miley who broke Beyonce's record for largest attendance at the London O2, with 16,196 in attendance.
I'd say they're about even in terms of touring.
Then there's the matter of TV, with Hannah Montana airing every day for 5 years in around
90 countries. That + the franchise products associated with it, in which Miley grossed an estimate $1 billion in the matter of a year. So... Miley.
After all this, I'd be inclined to say Miley is bigger worldwide, but Beyonce is great, and I don't want to anger any of her stans because I do love her.