From Marvel Database:
"
Superhuman Strength: In addition to being the God of Thunder, Thor is also the Norse God of Strength, as such he is physically the strongest of the Norse gods
[15][22][23][24][16][25] and one of the most powerful beings in the Universe.
[26] His strength has been called unlimited.
[14] His feats include easily lifting over a millions tons without any effort,
[27] crumbling Uru into dust,
[25] defeating and overpowering superhumans as strong and powerful as the
Silver Surfer,
Namor,
Juggernaut,
Hercules,
the Hulk, the
Red Hulk,
the Sentry, and
Gladiator in single combat, lifting the
Midgard Serpent,
[28] who was large enough to coil around the Earth from head to tail multiple times over and crush it in its grip.
[22], overpowering cosmic entities when pressed in battle and physically destroying stars, planets, and moons with only his fists.
[29][30] Thor also possesses a magical belt that doubles his natural strength. Thor is also capable of entering into a state of Berserker Rage known as Warrior's Madness, which will temporarily increase his strength and stamina tenfold but will only do so in desperate situations because it threatens his sanity.
[31][32][33][34]
Despite the fact that he always restrains and holds back his vast strength against mortals, he has been capable of stalemating an enraged Hulk in strength (depsite the fact that the Hulk was constantly increasing in strength every moment) for hours without tiring at all and while restraining himself as always,
[35] and knocking out the Hulk,
[36] How much strength Thor truly holds back against mortals is made clear, as he was capable of knocking out Namor with a single blow (despite Namor being fully hydrated and it was raining),
[37] easily defeating Bi-Beast (whose strength is said to equal the Hulk's),
[38] easily overpower the Red Hulk (who killed the Abomination, overpowered the Hulk, punched and injuring Uatu, killed the
Grandmaster, and was able to absorb the Power Cosmic), nearly rendering the Juggernaut uncouncious in under a minute after negating his mystical defenses,
[39] and defeated both
the Thing and an enraged Hulk at once in unarmed combat using only his vast physical strength.
[40]"
[...]
"Strength Level: Class 100+ ; Thor possesses vast physical strength, to which the exact limit is unknown, but he is able to lift far in excess of 100 tons effortlessly. He has shown enough strength to move and lift objects that are as heavy as the Earth and shatter entire planets with his blows. Thor is physically one of the strongest beings to ever walk the Earth and one of the most physically powerful beings in the Universe."
http://marvel.wikia.com/Thor_Odinson_(Earth-616)