What Is Penny’s IQ in ‘The Big Bang Theory’?

The Big Bang Theory may have wrapped up back in 2019, but the long-running sitcom has left an indelible impression on its many fans and continues to be a touchstone for pop culture lore. A lot of what makes the show so enduring is its unique characters

While some have criticized The Big Bang Theory for lazy storytelling and an over reliance on tried-and-true stereotypes, it certainly broke ground with representing a particular kind of nerd culture that had rarely been seen on primetime TV — and certainly not through the eyes of the main characters. Rather than relegating the nerds to quirky sidekicks, The Big Bang Theory put the smartest people in the room front and center. In a show where exceptional IQ became the norm, one outlier was Penny. How far was her IQ from her friends’? 

‘Big Bang Theory’: Penny acted as a foil to Leonard and Sheldon

Putting opposites together is a longstanding tradition for bringing about comedy gold, and Chuck Lorre — the creator of The Big Bang Theory and other hit sitcoms like Roseanne and Dharma & Greg — is a master at the technique. In the case of The Big Bang Theory that opposites-attract chemistry was captured in Penny (Kaley Cuoco), an aspiring actor who lives across the hall from a pair of genius astrophysicists named Leonard (Johnny Galecki) and Sheldon (Jim Parsons).

Penny’s tell-it-like-it-is personality and brash street smarts are a stark juxtaposition to Leonard and Sheldon’s quirky social awkwardness and generally reserved demeanors. As Leonard makes it his mission to win Penny’s heart, Penny decides to help her neighbors break out of their shells and experience more of the world beyond their work and apartment.

Penny was a last-minute addition to the series, which originally pitched the men allowing a divorcing woman named Katie to live in their spare bedroom. Adding a little distance and making Penny a bit less abrasive than Katie, the show hoped to provide a more likable character.  

Penny’s IQ is not as high as the stars of the show

Leonard and Sheldon are undeniably the protagonists of The Big Bang Theory, and their identity is very much centered on their intelligence. Both Leonard and Sheldon are portrayed to be exceptionally gifted individuals. Sheldon — whose precocious genius was later explored in the prequel spinoff Young Sheldon — graduated college at 14.

By sifting through some clues on the series, fans were able to determine that Sheldon has an IQ of 187 and Leonard has an IQ of 173. These are off-the-charts levels of giftedness. For comparison, Healthline reports that both Albert Einstein and Stephen Hawking are estimated to have had an IQ of 160. 

Penny, meanwhile, has an IQ of 97, as CBR reports. It’s also worth noting that the show goes out of the way to display Penny as not very bright: “she was dense enough to think the Cold War was fought in winter” and  “she didn’t even know how to spell Asthma.”

Penny is smart in other ways

Penny (Kaley Cuoco
Penny (Kaley Cuoco | Sonja Flemming/CBS via Getty Images

While IQ is the widely accepted way to measure someone’s intelligence, plenty of recent research has questioned whether this method is particularly useful. After all — and as The Big Bang Theory itself demonstrated — those with incredibly high IQs can struggle to maintain social ties and can close doors to opportunities with a lack of other skills. 

While Penny is undoubtedly less intelligent than Leonard and Sheldon academically, she was able to hold her own in other ways. The Things points to an episode where Penny beats Leonard at chess as evidence that she’s able to play up her social skills — and even use her “dumb blonde” reputation — to her advantage. By disarming Leonard by playing dumb and calling the pieces by silly names, she’s able to distract him from her plot to defeat him. 

This scene acts as an undercurrent to Penny’s strengths overall. She may never be headed to the top of an Ivy League school, but she’s managed to find her footing in the world, and she has a thing or two to teach the guys as well. 

RELATED: ‘The Big Bang Theory’: What Is Kaley Cuoco’s Favorite Episode?