‘Big Bang Theory’: How Its Ratings Are Different Than Every Other Show’s

Everyone knows CBS’ sitcom “The Big Bang Theory” is popular. What’s stunning is just how long its popularity has lasted.

The series about lovable, math-obsessed nerds is by far the biggest comedy on television, as it has been each of its past six seasons. After 205 episodes, that is nothing short of astonishing.

“BBT” – which has its season finale next week – averaged 8.4 million total viewers its first season. By the next year, that had grown to a cool 10 million. This year, in its ninth season, the show is averaging more than twice that, pulling in a whopping 20.3 million viewers per episode. (These and other numbers conform to Nielsen’s “most current” metric, which counts seven-day delayed viewing where available.)

In the advertiser-coveted adults aged 18 to 49 demographic, “BBT” scored a 5.7 this season, nearly doubling the 3.3 rating from season 1.

That marks the fourth-straight year (fifth overall) “BBT” has been top comedy in the demo.

That puts “BBT” in the company of such classics as “Friends” (six seasons at No. 1 overall) and “Seinfeld” (four seasons).

How in the ever-expanding universe is such sustained success possible? We won’t tackle the popular debate over whether or not “Big Bang” is among the funniest comedies on TV here — the show’s enviable Emmy track record is on the side of hardcore fans — but its actual business impact remains undeniable.

Before we go any further, however, we should flag one potentially misleading part of “BBT’s” massive numbers right up front. While live tune-in was far more common years ago when “Big Bang” began, the adoption of DVRs and on-demand viewing was still in its infancy. So, while the Live + 7 Day statistic is still the most appropriate way to perform a comparison, it is by no means perfect.

Drilling a little deeper into the numbers, we can see that “Big Bang Theory’s” biggest season was 2013-2014, when it topped off at a 6.4 rating and a rounded 20.4 million total viewers. Those numbers, again, are for a sitcom well past the 100-episode mark.

Take a look at the series’ progression below, first in the key demo ratings, then in overall audience size.

TV Ratings, 18-49 demo
Season 1: 3.3
Season 2: 3.8
Season 3: 5.4
Season 4: 4.5
Season 5: 5.6
Season 6: 6.3
Season 7: 6.4
Season 8: 5.7
Season 9: 5.7 to-date, will likely decline by finale

Total Viewers
Season 1: 8.4 million
Season 2: 10 million
Season 3: 14.4 million
Season 4: 13.4 million
Season 5: 15.9 million
Season 6: 19 million
Season 7: 20.4 million
Season 8: 19.3 million
Season 9: 20.3 million to-date, will likely decline by finale