How fast can the superhero Flash run?

The superhero Flash possesses immeasurable "super speed" but is faster than Superman, according to DC comics, who is undeniably faster than a speeding bullet. Flash, also known as the Scarlet Speedster or the Crimson Comet, is the fastest man alive among superheroes.

Flash became superhuman after inhaling gases from a botched experiment and took on the powers of the speed god Mercury. Powered by the speed force rather than the laws of physics, Flash's speed is not limited to running. Flash thinks as fast as he runs, which makes reading his thoughts difficult, and he can punch someone one billion times per second.