Supergirl Is More Powerful Than Superman - Here's Why
The 2026 Supergirl movie, which hits cinemas on June 26, will feature a version of Kara Zor-El that's a little different from previous adaptations. From the snippets of the character (played by Milly Alcock) we've seen in trailers, she feels tougher, more detached, and not especially interested in fitting into the version of heroism that her cousin Kal-El represents.
That idea is not new, but it is being pushed to the forefront this time. And it ties directly into the decades-long question of which cousin is more powerful. Supergirl is not technically more powerful than Superman. In most versions of the comics, he still comes out ahead when you factor in his fighting experience and his long-term exposure to Earth's yellow sun.
However, there are several consistent reasons why Supergirl often comes across as stronger, and in some stories, she actually is. That's because Kryptonian strength is not really tied to physical size or build. Both Kara and Clark draw their abilities from solar radiation, which enhances everything from their strength and durability to flight and heat vision.
This is established across decades of comics and is reflected in stories like 2005's All-Star Superman, where Clark's power increases dramatically with additional solar exposure. But unlike Kara, Clark was raised on Earth by the Kents where he learned from a young age that even small mistakes could hurt people. As a result, he developed the habit of holding back.
Superman's Biggest Limitation Is Himself
Superman confirmed this character trait in 2004's Justice League Unlimited Season 3, Episode 13, titled "Destroyer." During a battle with Darkseid, he says, "I feel like I live in a world made of cardboard, always taking constant care not to break something, to break someone. Never allowing myself to lose control, even for a moment, or someone could die."
Kara does not approach her abilities the same way. In most modern versions of her origin story, Kara grew up on Krypton before being sent to Earth, which means she was already familiar with her own strength in a high-gravity environment. When she gains her powers under Earth's yellow sun, she is not learning from scratch in the same way Clark did.
Instead, she adapts quickly and tends to use her abilities more directly. This difference is noticeable in stories like Superman/Batman: Apocalypse (2010), where Kara is portrayed as significantly more volatile and, at times, physically overwhelming in a way that even Superman struggles to manage. That lack of restraint is one of the main reasons she appears stronger.
Supergirl's attacks also seem more forceful because she's not constantly filtering herself. And that changes how her power is expressed. In "The Supergirl from Krypton" story arc in 2004's Superman/Batman, the Dark Knight suggests that her body may have absorbed large amounts of solar radiation during her journey through space.
Why Supergirl Feels Stronger
Batman also theorized that Kara processes solar radiation more efficiently than Clark, which allows her to obtain more power levels in a shorter time. While her cousin benefits from decades of continuous sun exposure, Kara's faster absorption rate closes that gap. All these explanations reinforce the idea that Supergirl is stronger and faster than Superman. But only under certain conditions.
There are also alternate versions of Kara that push her potential even further. Power Girl, for example, is an alternate version of Supergirl from Earth-2 who survives the events of Crisis on Infinite Earths (1985), a storyline that wipes out entire universes. And in the 2021 Crime Syndicate comic series, Supergirl defeats Ultraman, an alternate version of Superman who is portrayed as extremely powerful.
It remains to be seen how the new Supergirl movie handles the perceived power imbalance. DC film adaptations rarely follow one version of a character exactly, and a lot of things that are canon in the comics change, depending on the story being told. Alcock's Kara is already being framed as less restrained, which could naturally make her feel more powerful in action.
At the same time, the film (and by that I mean its creators) will ultimately decide what is and is not canon within its own version of the DC Universe, so any comparison between Supergirl and Superman will depend entirely on how those rules are established.
