Depending somewhat on the nature of the battle, Hercules would almost certainly win a fight against Beowulf. Hercules is a demi-god, the offspring of Zeus and Alcmena, a human.

Beowulf is presented in the epic poem of his name as a human, a warrior and a king, and would be no match for what must be perceived as an immortal hero.

“Hercules” is a Roman extension of the Greek name “Heracles.” To a large extent, this Greek hero was mostly a human who became an immortal because of his remarkable achievements.

The Roman myth, however, retained all of the great stories and added many more that seemed beyond mortal abilities and made the character much more god-like. And because of his fabulous feats, Hercules joins the gods in the Roman Pantheon after his death.

Hercules is credited with what originated as the Ten Labors (he was assigned two more because he received help in killing the nine-headed Hydra and he was paid for cleaning out the Augean Stables) which overshadow almost any possible comparison to other heroes.

The “Dodekathlos” included killing the Nemean Lion, the Hydra and the Stymphalian Birds as well as capturing four dangerous beasts. There is no hero in Western literature that even approaches these triumphs.

Beowulf is known from the epic poem for three great attainments and one other accomplishment that is referred to from his past. In the epic, Beowulf kills a monster named Grendel, the monster’s mother and a dragon.

In a passage describing Beowulf’s youth he is credited with killing a couple of sea creatures, “nicoras,” during a heroic swimming contest with another warrior.

The Beowulf epic shows a progression of the hero toward more fabulous or magical successes. He is first credited with killing a couple of beasts in the ocean using his bare hands. Then, without armor or weapon, he tears an arm off of Grendel at the shoulder.

Next, he follows the badly injured, dying monster into a water “feature” and kills its mother with an enchanted sword found in the lair. Finally, 50 years later he slays a fantastical dragon with that same magical weapon. Beowulf dies from his wounds in the dragon battle.

It’s important to note that Beowulf is the most remarkably successful of the Germanic (Teutonic) heroes. Other major legends are developed around killing one dragon, or one monster, or one dangerous beast. Beowulf destroys five “forces of nature” in total during his long life.

Hercules finally dies as a result of reversed fate. His jealous fourth wife puts him into unbearable pain with a shirt that has been soaked in the poisoned blood of a centaur. Hercules had killed the centaur with a poisoned arrow.

Hoist on his own petard, Hercules builds a funeral pyre and one of his friends (various tales offer three or more names) throws a torch to the wood which burns him alive. Allegedly, the flames were less painful than the poison.

The legends claim that only the human aspects of Hercules were burned and then Jupiter (or Zeus in the Greek myths) brought the god-like aspects into the Pantheon (Greek Olympus).

The status of Hercules as a demi-god, apparently indestructible by humans, beasts, and fantastic entities, would result in the Greek/Roman hero defeating Beowulf in a battle. The converse would not be plausible. Any killing blow by Hercules would, in fact, kill Beowulf.