Is he strong as Superman, or a lot weaker.

it depends how you look at it
His durability should be higher, Thor has better feats for soaking damage from powerful entities and he doesn't have a weakness to magic or kryptonite
Superman would be much faster and has better feats lifting ships, lift up buildings, aircraft etc Thor doesn't really lift things like Herc or Superman, Thor brawls, fights, hammers 
Thor's standard equipment is the hammer, he comes with it just as Cap has a shield or Wolverine claws. The hammer is a skyfather weapon it has far more strike power and plot device powers than Superman got
Thor depends too much on the hammer, I'm not sure his fists can dish out that much damage. Superman gets his powers from kryptonian DNA and the Sun, he isn't dependant on a mystic weapon.

Depends on the versions of the comic book characters that you're comparing. For example: Classic Thor, Silver Age Superman, current Thor etc.

Does his strength come from his hammer or is he strong because he's an elder goddess/Asgardian hybrid? 

@X_Titans said:

Does his strength come from his hammer or is he strong because he's an elder goddess/Asgardian hybrid?

The latter; he's the son of Gaea and the son of Odin. Hybrid.

Superman and Thor both have deus ex machina level strength. So their strength will be as needed for the storyline, at the discretion of the writer. 

Thor has Busted planets and Been called a Planet buster many many times, as well as he easily beaten and overpowered planet busters. he's even beaten People who ripp apart atars and take solar system busting attacks.  and easily Koed Planet busters. he ususally holds back though  Thor's strength comes from his heritage. The hammer gives others the power of Thor. without the Hammer Thor is every bit as strong durable and fast. his lightning and weather manipulation comes from withiin.  in terms of Raw physical strength. He has Lifted and hurled the Odinsword which was so heavy even odin could not calculate it's weight(and Odin is way smarter than any earth born mortal) Uncoiled and lifted the Worldserpent. which would have weighed more than continents. he also had to overpower it to uncurl it. He shifts the earths axis by Arm wrestling the Immortal Hercules. He also turned back the worl engine (which was warping reality on a multi-dimensional level while he was a mortal. People Like an amped up silver surfer. an Amped up Drax the Destroyer, and A Stronger future version of Gladiator have all been overpowered by or admitted to being weaker than the Mighty Thor. He is definetly one of Marvel's strongest heroes and has a planetary level strnegth like Superman. they are in the same league of Strength at least. But I would say that with Miolnir Thor hits conciderably harder.   Thor is morre Durable than Superman He waded through blasts from classic Odin (who had easily busted Galaxy's) took Multiple blasts from an Amped up silver surfer beforre he even dropped his hammer. took (planet shattering blows without yeilding a single inch" (Superman is usually KOed by planetary level attacks) took a doomsday weapon to his dome when he was already uncounsious and didn't get a single scratch. BRB who has Thor's powers survived a hit that literally shattered an entire planet when he was already uncounsious. He also tanked a hit with "the power of a thousand suns" that was meant for Surtur. He's also taken hits from Galactus, Korvac, multiple plasts fom the entire fourth host of celestials, Hits from TOAA(the leader of the celestials not literal God) and attacks from Zelia (who is skyfather level on her own, after she had absorbed the entire race of dark god's strength as well as the Odinforce) and an attack that had all of Glory' power behind it.(Glory has the strength of an entire pantheon of 10,000 space Gods and all the worlds they were worshipped on)

Superman is faster and has a more diverse power set, but I agree with previous posts that Thor is tougher and more durable. Kal-El is from an advanced race, but Thor is from a warrior race. Superman is a super man, but Thor is a super warrior. By that I mean Superman loves to save people by fighting, but Thor just loves to fight. I think the more Supes knocks Thor down, the happier Thor will be each time he gets back up and Supes just wouldn't be able to keep up in the end. 

@SC said:

Superman and Thor both have deus ex machina level strength. So their strength will be as needed for the storyline, at the discretion of the writer.

This has proven to be true.

I'm a Thor fan.  But Superman is far stronger than Thor and anyone else in the MU.  Superman is credited with enough strength to move 1/3 of this planet.  Along with Wonder Woman and Martian Manhunter , they  did it.   For the sake of arguement.  When the Thing first reveled his strength level it was 5 tons.  And he fought the Hulk a few issues later.  DC amped their guys up far above the Marvel conterparts.

Thor is stronger than Superman.

both some of the strongest heroes of their universe. you can not really tell who would win in an one on one battle

but fact is that thor really has no weakness against something like kryptonite. maybe without his hammer he would loose against superman

with his hammer his powers are way powerfull than without it

can't really compare both characters in my opinion

@PowerHerc: @SC: isnt Thor just as stroung as hercules??? whitch hould make thor strounger than supes??

@Z3RO180 said:

@PowerHerc: @SC: isnt Thor just as stroung as hercules??? whitch hould make thor strounger than supes??

Marvel has shown Hercules and Thor to be roughly equal in strength, though they have given Hercules a slight advantage in two separate editions of the Official Handbook of the Marvel Universe.

Except for the Golden Age version and possibly the current rebooted version (so far), I'd say all mainstream DC universe versions of Superman is/was stronger than both Hercules and Thor.

I am going to open myself up for mass ridicule for this but...

The original marvel universe listed Thor at 95 tons. I know he has had many feats beyond this level so please spare me all the "showings" of greater feats. In my mind and my opinion this is what the creators of Thor intended his strength level to be. In my opinion with all of Thor's other powers and abilities granted to him by Mjolnir 95 tons is enough (waits for the attacks).

Superman on the other hand was listed in the first Who's Who as being able to easily lift the great pyramid (6,000,000 tons).

So in terms of strength again in my opinion Superman is far beyond Thor in terms of strength.

I know this are handbooks and a lot of people hate the handbooks and yes they have been updated. I am just giving my two cents on the thread. Writers come and go make changes etc, but if there isn't a logical explanation (like colossus getting older so stronger) then I am old school and go by the original stuff.

@PowerHerc: Agreed. I will say I think Hercules is stronger than Thor in terms of pure lifting strength/power.

@PowerHerc said:

@Z3RO180 said:

@PowerHerc: @SC: isnt Thor just as stroung as hercules??? whitch hould make thor strounger than supes??

Marvel has shown Hercules and Thor to be roughly equal in strength, though they have given Hercules a slight advantage in two separate editions of the Official Handbook of the Marvel Universe.

Except for the Golden Age version and possibly the current rebooted version (so far), I'd say all mainstream DC universe versions of Superman is/was stronger than both Hercules and Thor.

Well said my friend!

@Deranged Midget: @Valkaad: Thanks guys.

@venomyak said:

thor is a planet buster

@PowerHerc said:

@Z3RO180 said:

@PowerHerc: @SC: isnt Thor just as stroung as hercules??? whitch hould make thor strounger than supes??

Marvel has shown Hercules and Thor to be roughly equal in strength, though they have given Hercules a slight advantage in two separate editions of the Official Handbook of the Marvel Universe.

Except for the Golden Age version and possibly the current rebooted version (so far), I'd say all mainstream DC universe versions of Superman is/was stronger than both Hercules and Thor.

@daak1212 said:

Thor is stronger than Superman.

Explain?

@Z3RO180 said:

@PowerHerc: @SC: isnt Thor just as stroung as hercules??? whitch hould make thor strounger than supes??

Marvel has shown Hercules and Thor to be roughly equal in strength, though they have given Hercules a slight advantage in two separate editions of the Official Handbook of the Marvel Universe.

Except for the Golden Age version and possibly the current rebooted version (so far), I'd say all mainstream DC universe versions of Superman is/was stronger than both Hercules and Thor.

@Valkaad: Thor has lifted millions of tons without effort ...the handbook is like sayinf ..when superman was as powerful as a locomotive..or when he couldn't fly but leap tall buildings Thor has performed feats That would require strength to lift in excess of billions of tons

See my forum "Dc vs Marvel are equal?"

Forget preference. They are greatly evenly match. If any character is engineered to fight Superman, It would be Thor. He has no weakness and He is magic & science. Superman is more scientific with a weakness to the magic and his body feeds off of the sun but like necessary heal as fast as a Lobo or wolverine or Hulk; we saw this in Doomsday (Dc's Hulk) story. Take the best versions of each character, remove your preferences, stick to comic facts & powers & abilities.

about the same.

although THOR has better strength highlights.

THOR strength highlights has more meaning compared to superman's where its just about tossing a heavy item somewhere else.