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Quote
Goku>Superman
Raditz scanned Earth and found the average power level of humanity was 5.
Superman states he can lift around 100 tons.
Average human male can lift 40% of his bodyweight max (over his head whilst standing)
Average male weighs 80kg, 40% of 80kg is 32kg.
100,000kg divided by 32 = 3125. Superman can lift 3125x more than an average male. Thus has the strength of 3125 men.
If average power level is 5 then 3125 x 5 means Superman has a power level of 15,625.
Goku had a power level of roughly 10,000 normal when fighting Vegeta the first time, but raised it to 20,000 with Kaio-Kenx2 and 40,000 with Kaio-Kenx4.
So both Vegeta and Goku are stronger than Superman in the very first season of Dragonball Z,
thus ending the great Goku vs Superman debate.