'American Idol' finale draws fewer viewers than 'Big Bang Theory'

Fox’s "American Idol" concluded its 15-season run last night with an estimated 12.94 million viewers and a 3.0 rating/10 share in adults 18 to 49, based on the fast affiliate data from Nielsen, making it the show’s most-watched season finale since 2013.

Compared to last year’s season finale, last night’s show — which featured performances from more than 50 past contestants — was up 61% in total viewers and 76% in adults 18 to 49. Despite the improvement, the ratings were still far below the show’s most-watched season finale, in 2003, which drew 38 million viewers.

The much-anticipated — or at least much-hyped — show didn’t even manage to win the night. That honor went to CBS’ "Big Bang Theory," which scored 13.24 million viewers.

Not long ago, the "Idol" season finale was so dominant that competing networks would sit the night out, airing mostly repeats. But last night, only NBC featured anything second-run, and CBS boldly opened the second season of sitcom "The Odd Couple" at 8:30 p.m. after "Big Bang." (Though the Matthew Perry vehicle slipped 41% in total viewers.) 

Nielsen fast affiliate data is time-period based, meaning it only measured audiences for "Idol’s" scheduled broadcast period of 8pm to 10pm. The show ran six minutes long, and new winner Trent Harmon was not crowned until after 10pm. Fox is estimating a total platform audience of 16.5 million viewers (which includes the Live + 7 Day results).

"American Idol" did lead Fox to an easy nightly victory, with the results by network as follows:

Total Viewers:
Fox: 12.94 million, CBS: 7.32, ABC: 6.03, NBC: 4.88, CW: 1.64

Adults 18-49:
Fox: 3.0 rating/10 share, ABC: 1.6/ 6, CBS: 1.6/ 5, NBC: 0.9/ 3, CW: 0.6/ 2

Here are the ratings for season finales from all 15 seasons: