system
Given the following post, respond as if you're commenting on Reddit:
human
[One Punch Man] How strong is Saitama actually and why?

We’ve seen ‘consecutive normal punches’ as well as ‘one serious punch’ that didn’t even make contact with Boros, but how *stong* is Saitamas hit if it were to make contact? Also, is there more beyond the ‘one serious punch’?
gpt
From a purely internal viewpoint we've only confirmed he can strike hard enough to block a planet destroying blow (assuming Boros wasn't lying). So it is fair to say he can punch at least hard enough to destroy the whole planet. Borus also claimed that Saitama basically played with him during that fight so he's potentially greater than planet destroying but to what level we don't know.

Externally we know Saitama can hit as hard as the plot demands. Fundamentally the show is meant to explore what happens when the character gets no catharsis or development. He is forever trapped as an unbeatable force of nature who's existence is pointless due to a lack of challenge. It is why he's more excited for grocery shopping than fighting villains, shopping is more challenging.