While winning American Idol doesn't guarantee anyone a spot on the A-list (sorry, Taylor Hicks!), it can be a safe bet.
As everyone knows, even just appearing on the show can be a career launching pad.
Still, there always has to be a winner…even among winners. Billboard dared ask, "Mirror, mirror, on the wall, who's the biggest Idol of them all?" and ranked the top 24 most successful.
While Underwood may have sold the most records—11.5 million, to be exact—it's the OG winner, Clarkson, who's still tops after the trade mag calculated in radio plays and individual track sales.
Chris Daughtry landed in third, while Jordin Sparks and David Cook round out the top five. Other alums of note: Clay Aiken at No. 6, Adam Lambert at No. 12, Hudson at No. 13, Hicks at No. 19 and Allison Iraheta finishing in the bottom slot.