In 2013, Stan Lee iconically said, "The person who'd win in a fight is the person that the scriptwriter wants to win." He meant, essentially anyone could theoretically beat anyone if the comic creator concocted a situation wherein it would be possible.
Although, sometimes it's just fun to mash action figures together and see who would come out on top. But when doing that, it's important to remember the wise words of Stan the Man and to factor it into analysis.
Speaking of analysis, let's talk about methods. Like with many things, this endeavor to determine who would actually win in a fight revolved around a spreadsheet. The data in this spreadsheet was compiled from several comics, the official Marvel and DC encyclopedias from DK, film and television appearances, and, if all else failed, the official wikis.
All of that to say, there is a lot of data, and answers that may appear clean-cut are not necessarily as simple as they seem.
Like with any good spreadsheet, the numbers are likely an easy place to start.
According to the DC and Marvel encyclopedias, Clark Kent stands at six feet and three inches tall, and Thor is only three inches taller, but while Superman weighs 235 pounds, Thor nearly triples that weighing 640 pounds. This does mean that in terms of weight alone, Thor dominates over Superman.
But, size isn't everything.
Powers and Abilities
Powers are where the differences really start to become important. Both heroes have enhanced strength, longevity (which isn't listed for Superman but can be surmised based on any fight fans have seen the Man of Steel take part in), and - though it isn't listed for Thor, it can be presumed due to his long life - some kind of accelerated healing.
It can also be presumed though not listed that Thor, like Superman officially, is bulletproof, as something so human and mortal likely is nothing to a god. Though there is almost no distinction, it should be noted that while Superman is "invulnerable," Thor is "near invulnerable."
As for actual powers, comics Thor doesn't have many others without Mjolnir, besides one big one that will be discussed in a bit. Superman has super speed, freeze breath, laser eyes, and X-ray vision. With Mjolnir, Thor can channel storms, open portals, and make energy blasts. While Clark can simply fly, Thor can only do so with Mjolnir.
Both heroes have the ability to render themselves entirely powerless in some situations — for Superman, put him under a red sun, and for Thor, revert him back to Donald Blake, his civilian persona if that option is available.
The biggest difference when it comes to powers is in the weaknesses. Superman is weak to Kryptonite, so if Thor had some, he would win in an instant. Thor, on the other hand, does not have a comparable weakness.
Additionally, Clark is susceptible to magic, whereas Thor, thanks to the Odinforce, actually has magical abilities. This could prove interesting in a fight, as Thor can control one of Superman's only two main physical weaknesses.
Superman seems to win out as far as powers go, but the weaknesses aspect does give a little weight to the Thor side of things.
But what about putting those powers into practice?
Justice League/Avengers: Why the "Definitive" Answer Isn't So Definitive
In the early 2000s, Kurt Busiek and George Pérez brought fans the JLA/Avengers limited series, and in it, Superman did beat Thor. However, Superman says that Thor "may be... [the] single toughest opponent... [he's] ever-" before getting cut off, presumably before saying "fought."
This may seem like the end of the debate before it even truly begins. Superman beat Thor, and that's that.
But, it's important to remember the words of Stan Lee. While yes, the story is official canon, as confirmed by Busiek on social media in 2019, it presents the battle in a specific situation, with specific criteria, all of which were concocted by the writer and artist to present the story they wanted to tell at that moment in time.
In fact, as will be discussed in the next section, the rules of that fight and that crossover were different than the standard rules Superman or Thor could face in a typical fight.
However, it is worth acknowledging that yes, Superman has beaten Thor previously, so that would be a point to camp Superman.
Is Superman Worthy of Mjolnir?
In the JLA/Avengers title, Superman lifts Mjolnir, seeming to mean he is worthy of the hammer like Thor. He is actually not the first DC hero to do this, as Wonder Woman did in the 1990s DC vs. Marvel crossover.
While this may seem to suggest that Clark is worthy, it's not quite the case. After the fight is over, Superman attempts to lift the hammer again and can't. Thor explains, "There is an enchantment 'pon my hammer, laid by my father Odin. It is not... Easily lifted by others."
Clark responds, saying, "I held it before," to which Thor explains, "My father is stern, Superman. But not stupid. A very few worthies have been allowed to overcome the spell, in desperate hours." In other words, in desperate situations, certain people may be temporarily worthy of Thor's hammer (Think the scene with the kids in Thor: Love and Thunder, but a little pickier).
Thor does admit, though, "Perhaps it was but briefly... but it [Mjolnir] was in good hands" when Superman held it. Even if not permanently worthy, Clark has Thor's blessing as someone good enough to hold it.
It is worth noting, however, that in a 2019 comic Thor: The Worthy, silhouettes of seemingly both Superman and Wonder Woman are shown holding the hammer.
So, it's fair to say that Thor has the Mjolnir advantage over Superman.
How Do They Fare Against Proxy Heroes?
Now, to counteract the Stan Lee scriptwriter argument, it's always a good idea to compare multiple fights between the same opponents and see what patterns emerge and who tends to be victorious more often.
However, thanks to Thor and Superman coming from rival comic publishers, there aren't enough examples of them fighting to compare to one another. So, to get some results anyway, one must turn to "Proxy Heroes." This is not an official term, but it's a fair explanation for the role other heroes with a similar powerset will play in this argument.
On both the Marvel and DC sides of things, there are several characters that share similarities with a rival company's character — Hawkeye and Green Arrow, Quicksilver and The Flash, Daredevil and Batman, etc. This isn't to imply that one character is always a knockoff or play on the other (though in some cases it very clearly is), but that these characters are comparable when it comes to powers and abilities.
As such, one can look at how Thor has fared against Hyperion (a big, muscly, flying man with super speed, who can shoot energy beams from his eyes) or how Superman has done against Shazam (a mythology-based hero with super strength, magic, and lightning powers, who can revert to a weaker version of himself with a simple task).
An alternate version of Hyperion has been seen to destroy that universe's Thor, and Hyperion was stated as technically stronger than Thor in the Heroes Reborn event (see this rundown for more details). However, Thor did ultimately beat Hyperion in that very same event. Again, the situations created by the writer and artist call for different results in order to tell the specific story being shared.
On the other end, Superman has beaten Shazam on a couple of occasions. But, in some notable fights, Clark did so by covering Billy Batson's mouth when he returned to his kid form, preventing him from powering back. This option wouldn't exist with Thor unless the Donald Blake rules were in play, and Thor was separated from Mjolnir long enough to revert him to that mortal form, and Superman was able to prevent him from getting Mjolnir back. But, Shazam and Thor are certainly not a one-to-one comparison, so some of that balances out.
Supergirl vs. The Mighty Thor
It should be made clear from the beginning that Kara Zor-El's Supergirl and Jane Foster's Mighty Thor are not just "female versions" of Superman and Thor Odinson, but whole and unique characters in their own rights.
Furthermore, they do not necessarily represent their male counterparts exactly, as Supergirl has been stated to sometimes be stronger and faster than her cousin (again, the Stan Lee quote comes into play; this can change depending on what the writer and artist want), and The Mighty Thor sees her mortal form weaken every time she picks up the hammer and dons the armor.
That being said, it is worth looking at how the two heroes compare, as it can lend some context to the Superman vs. Thor debate, as well as give fans more evidence to consider when it comes to this Asgardian vs. Kryptonian conundrum.
Kara stands at five feet and five inches tall, whereas Jane - when powered up - stands at five feet and nine inches tall. Additionally, Kara weighs 120 pounds, while a powered-up Jane weighs 450 pounds, according to the Marvel Wiki. Like with their male counterparts, the Asgardian definitely bests the Kryptonian when it comes to these physical stats.
One of the biggest differences between the two, and a difference that wouldn't typically apply to the Superman vs. Thor debate, is that Kara has had her powers and abilities since she first came to Earth when she was a teenager, while Jane was an adult the first time she lifted Mjolnir. Kara certainly bests Jane when it comes to experience, though Superman and Thor both grew up with their powers.
Interestingly, Kara and Thor Odinson share the similarity of having grown up in the foreign world that gave them their powers, while Clark and Jane had to learn about it as they went along. That is one of the few similarities wherein the counterparts are flipped.
Ultimately, a comparison between Supergirl and The Mighty Thor would need its own article, but the information here is helpful context when looking at the Thor vs Superman debate.
Who Comes Out on Top?
While Superman and Thor both have compelling arguments and have been proven to be a relatively even match, Superman ultimately would win the day, unless Thor had Kryptonite on hand.
Extrapolating the powers and abilities of both, Superman's do seem to dominate, especially since they all come from him, rather than many coming from tools like Mjolnir or the Odinforce.
As always, though, different situations from different creators will lead to different results. The joy of comics is getting to see so many different writers and artists play with their characters differently, leading to new and exciting situations to read.
All of this is to say: This could be proven wrong one day by a new comic, which is then contradicted decades later in another story.