I always wondered what Barry Allen's top speed is in The Flash (CW), as it's never really stated or estimated.

What is the top speed of the Flash?

  • You may be getting voted down because this isn't particularly hard to research online.
    – iandotkelly
    Oct 18, 2020 at 16:42

2 Answers 2


The information provided in this answer isn't really correct on Barry's top speed. As far as I'm aware, and I watched the show up to season 6, Barry's top speed was revealed in Season 4, Episode 15, called "Enter Flashtime".

In this episode, a nuclear bomb is detonated, and all of Barry's friends are in the site of the nuclear explosion. So in order to save everyone, Barry got so fast, he was able to hold multiple conversations with other characters, walk sort of casually, and run to "charge up" then throw a lightning bolt, all while the nuclear bomb was, well, blowing up. He also left the site of the explosion, went to Star Labs to talk to Iris, and did some other things.

According to the YouTube Channel "Comic Books vs. The World", his speed was around 99.9999% the speed of light:


After a lot of research, I found out Barry's top speed.

In S6, Gideon tells Barry that ultraviolet light travels at a speed of 186,000 miles/second, and that the current Barry is 80 times slower than that, so we can do the math and check it out:

186,000 miles/sec/80 = 2,325 miles/sec (Barry's top speed)

This converts to:

2,325 miles/s = 8,370,000 miles/hr = 13,470,209 km/h = 3,741,724 m/s = Mach 10,909

  • All light travels at 186,000 miles/second and since Barry can literally run fast enough to travel through time it seems likely that his maximum speed is faster than that. I am not aware that any actual maximum has been defined.
    – Paulie_D
    Oct 18, 2020 at 16:47
  • At this speed (c/80), when he travels a full day, the time elapsed for everyone else would be 1 day + 6 seconds ... A "slow" time travel...
    – Déjà vu
    Oct 19, 2020 at 1:08
  • 1
    I haven't watched S6 yet. Does Barry have a brain tumor or a lobotomy in S6? He's a scientist, why would he need a super-advanced omniscient Artificial Intelligence to tell him the speed of light? Oct 20, 2020 at 7:40
  • @JörgWMittag What kind of scientist is he? It's been a while since I've seen the Flash, but I thought he was a forensic scientist, so he would have no need to know the speed of light.
    – user25730
    Feb 23, 2021 at 6:06

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