DC’sFlashis unbelievably fast,leaving even Superman in his dust. Flash is so fast that he can be in multiple places at once and even run back in time. However, despite being the Fastest Man Alive, there’s one limit that Flash still has to surpass, and even DC admits it.
Flash Is Fast, But His Speed Can Still Be Measured
The Fastest Man Alive Gets Called Out, Even as He Puts a Number on His Speed
In Ian Flynn and Adam Bryce Thomas’DC x Sonic the Hedgehog, Flash meets the only other hero who might be worthy of his title - Sonic the Hedgehog. The two immediately strike up a competitive friendship, showcasing their superspeed as they take on Darkseid. But when Flash boasts that he can move within a picosecond, Sonic shoots back,“Aw, your speed can still be measured? That’s adorable!”
This initially seems like it’s just trash talk between two rivals, butthere’s compelling evidence to suggest that Sonic reallydoesoccupy a level of speed that the Flash still hasn’t reached.

Is Sonic Really Faster Than The Flash? It Really Looks Like It
Sonic and Flash race repeatedlyacrossDC x Sonic, with the Blue Blur repeatedly taking the lead. However, it’s when Sonic trades places with Flash that he shows his true speed. Battling Reverse-Flash, Sonic speedily swaps out the villain’s Chaos Emerald then beats him up, with Reverse-Flash totally unable to understand how Sonic could be so fast.
Reverse-Flash and Flash generally have similar speeds, with Reverse-Flash being slightly faster in some cases. However, in this fight, Sonic is so fast that Reverse-Flashdoesn’t even see him move. This is fascinating in the context ofSuperman #709(by J. Michael Straczynski, Chris Roberson, Eddy Barrows and Allan Goldman), where the Flash states he can see events which last for less than an attosecond - a unit of time equal to one quintillionth of a second. This is the speed Sonic would need to surpass to be invisible to the Reverse-Flash.

Flash Follows Physical Laws, But Sonic Doesn’t Have To
Even not taking that measurement into account, the series itself states thatFlash moves in a matter of picoseconds(one trillionth of a second), with Reverse-Flash keeping up with his heroic nemesis. It certainly seems that Sonic has access to a level of speed that Flash can’t even fathom.
There’s actually likely a canon explanation for this. In DC lore, different realities have different laws of physics. DC has multiple ‘cartoon’ realities where physical harm is impossible (like Earth-42), and where physics are more extreme. It seems that Sonic the Hedgehog simply comes from a reality where speed surpasses any form of measurement, while Flash - despite being so fast he can travel through time - still hails from a more grounded world where speed is always measurable.

Flash often seems overpowered in DC lore, with his speed allowing him to accomplish almost anything, including rescuing hundreds of thousands of people in the blink of an eye. However, Sonic the Hedgehog simply doesn’t have to play by the same rules, meaning thatFlashwill always lag behind the Blue Blur when it comes to raw speed.



