Originally Posted by
Nik Hasta
Basic Saitama Speed Breakdown
As with every discussion involving Saitama, the usual caveat applies. Even as far as we are in the original manga, we have never seen Saitama even get close to going all out.
However, we can look at the speed algorithm of everyone else and work out what his absolute minimum has to be. This will contain minor spoilers for a fight or two.
So... I guess Genos is a useful enough measuring stick.
When he appears, Base Genos is capable of tearing the legs of a superspeed enemy in flight with such speed and precision that they don't even notice that their legs have gone until they see him holding their legs. He outruns his own incinerator blasts to their targets and generally pulls off your standard anime blink movement thing.
So, soft pitch at high endish bullet time, maybe?
Likely faster.
First time Genos, who is still in his base body, encounters Speed of Sound Sonic, Sonic blitzes around him with impunity and Genos is like; "Huh, he's pretty crazy fast,"
So, we're a solid tier up on high end bullet timerish right there.
Genos then gets his upgraded body and gets into another fight with Sonic later on. Sonic and him are fairly even now so Genos has reached the same level. Genos then "accelerates," and starts utterly overwhelming Sonic, deliberately snatching bits off his clothes, making him look like he's real slow. So that's another level up.
Sonic then activates his own superspeed technique, Four Shadows Burial, and he's at a level of speed that Genos can barely perceive so his only option is to try and counter with an AoE. So that's another level up, quite a steep one at that.
So, flash forward to the Garou arc, which is currently only in the original webcomic so this may change when Murata gets to this part, and we see Genos, enhanced body and all, fetch up against Gums and Black Sperm and they both tear him to pieces faster than he can react. Add another order of magnitude onto that and kiss Genos goodbye because he has ceased to be relevant. Bang then goes in on the same monsters and pretty much blitzes them with ease, which is another order of magnitude. Shortly after this, Black Sperm unifies all of his cells to become Golden Sperm and he's on a level where he's even effortlessly blitzing Tatsumaki, who was casually monstering on everyone at that point.
Garou then rocks up, blitzes /everyone/ including Golden Sperm and specifically notes that he's not really having to try that hard.
He then... finally, fetches up against Saitama and is still utterly outclassed by a non-serious Saitama.
So... to recap, that's... ten orders of magnitude above high end bullet timerish to get to Saitama and that's still Saitama when he's not trying.
He's certainly in the high multiples of mach. Somewhere in the hundreds or something.
This isn't fully complete but it's a good indicator of his speed.