Goku’s power level is rumored to be over 9000.
This answer has been a matter of much debate and speculation among the Dragon Ball fan base, but one thing is certain: He really does have an abnormally high power level.
It was revealed in the episode “Goku’s Ordeal” that when he first started training under Kama-sama the god of martial arts, she measured his Ki at 5,000. Assuming that Kami-sama’s measurements are comprehensive and accurate (we do not know if this power reading would include or exclude latent potential), it seems fair to say that Goku most likely has trained himself to 9x his initial ki levels in pursuit of obtaining some superhuman abilities.