It has already been established that the Flash can reach and surpass the speed of light. However, if has also been made explicit that such a feat is not easy for him, as it's not cheap in terms of possible consequences.

As such, I assume that could be considered like the top of his range, a sprint that he can perform but he'd rather not, as opposed to something he can do and maintain for an extended period of time (like jogging for a standard human).

However, some comics illustrate him performing feats such as moving around without people right beside him even perceiving he's gone, a feat that is only possible if he's gone for less than 1/50 seconds. This puts his his speed at a minimum of Mach X for each 5 meter radius, that is Mach 10 to affect something that is 50 meters away.

My question is, what is the standard speed (broadly speaking) that the Flash uses on a day-to-day basis (or the range of that speed) and what speed does it become an effort or strain for him to maintain?

We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.

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    This depends on which continuity you refer to. In most canons, his "cruising" speed becomes higher the more he practices.. Anyway, I think a more interesting question would be what acceleration he can achieve. – Mr Lister Feb 9 '16 at 19:05
  • If there are several answers for different continuities I would be interested in all of them. Regarding acceleration... I think that only counts when reaching extra high speed levels, on most of the rest of action it is depicted as instantaneous (i.e. he simply pull off the feat, there's no build up of speed to get it done) – Jorge Córdoba Feb 9 '16 at 19:40
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    I would suggest that asking for all continuities would be too broad. There have been dozens of DC continuities, most of which have a Flash. – Politank-Z Feb 9 '16 at 19:44
  • I expect most of them to be consistent among them, that is, I would not expect ALL of them to have significant differences. I.e. if Continuity 1 Flash moves at Match 20 and Continuity 2 moves at Match 30 I consider them to be on the same "range" ... and I expect that to be similar on most continuities any way. – Jorge Córdoba Feb 9 '16 at 19:46
  • You also have to remember the bulk of those continuities are not points, but progressions. In the various comics, and the TV show, he always starts going slower than at the end (or, if the plot calls for it, he starts fastest, then loses speed and has to gain it back, because reasons). So for all continuities, there will be a series of ranges depending on which point you look at. – Vogie Feb 10 '16 at 13:09

Since his top speed varies so wildly from author to author and continuity to continuity, there's no way we're going to be able to pin down a "comfortable" run speed with 100% precision. It's hard to imagine why an author would bore a reader with his ho-hum speed. Usually, numbers are only going to be used when talking about a feat that's crazy fast, even by the Flash's standards.

All that being said, we should still be able to calculate something reasonable.


Normal Male

  • Top Speed: 15.9 mph
  • Jogging Speed: 8.3 mph (52.2% of top speed)

The Flash

Based on calculated speed:

  • Top Speed: 8,937,608,400,000,000,000,000 mph
  • Jogging Speed: 4,665,431,584,800,000,000,000 mph (52.2% of top speed)

Based on written speed:

  • Top Speed: 670,616,629 mph (speed of light)
  • Jogging Speed: 350,061,880.338 mph (52.2% of top speed)

Your question has 2 parts:

what is the standard speed (broadly speaking) that the Flash uses on a day-to-day basis (or the range of that speed)


what speed does it become an effort or strain for him to maintain?

First we need to establish a baseline with a normal/average person. I've seen several exercise websites list a good treadmill jogging speed as between 5 and 6 miles per hour (such as this one and this one, for example). I tend to trust high-profile news sources more than I trust exercise recommendations from the internet so I found this article from The Telegraph that says:

The average man jogs at a speed of 8.3 mph

We'll go with that.

The same article gives us a sprinting speed of 15.9 mph.

So, we can use these numbers to say that an average male has a standard, maintainable speed of 52.2% of their top speed.

To extend this calculation for The Flash, we need to know his top speed. The fastest speed I've been able to find is from this image:

enter image description here

We have a discrepancy here because the author clearly notes the speed as just short of the speed of light but further inspection of the feat itself proves otherwise.

Based on the above calculation, The Flash can travel up to 2,482,669,000,000,000,000 miles per second. Converted to miles per hour, that's 8,937,608,400,000,000,000,000 mph. That's unimaginably fast...

Given that top speed, we can estimate his comfortable jogging speed at 4,665,431,584,800,000,000,000 mph, or 6,956,927,972,032.14 times the speed of light.

If we allow the author a little breathing room and place The Flash's top speed at the speed of light (670,616,629 mph), that puts his comfortable jogging speed at a much more modest 350,061,880.338 mph or 456,244 times the speed of sound.

  • The math adds up, and the calculations are mind-blowing. I laughed for like 3 minutes on the calculated jogging speed. Well researched and well done, +1 to you sir. – Anoplexian Feb 17 '16 at 16:47
  • His top speed must by necessity be much, much higher than those ≈8.9 sextillion mph, since that is assuming that his speed is constant. But picking up a Korean (or any human) at that speed would undoubtedly break their body in half, so he would have to reduce his speed at least about 99.99% in order to actually pick up and set down said Korean. Given that he has to do that a million times in 0.00000000001 seconds, the speed he reaches in between, when at maximum speed, must be basically too high to fit in this comment field. – Janus Bahs Jacquet Feb 19 '16 at 18:14
  • Also, 8.3 mph is a pretty damn fast ‘jog’ for an average person. I’m no avid runner, but I’m a decent runner, and I can’t sustain 8.3 mph for more than perhaps a mile or so. From anecdotal evidence (i.e., people I’ve run with and numbers I see on treadmills at the gym), the average jogging speed is more like 7–7.5 mph. – Janus Bahs Jacquet Feb 19 '16 at 18:16
  • What is relativity. – Race Bannon Feb 19 '16 at 18:34
  • It's not necessary that the Flash actually started moving them right when the bomb went off, in fact if he had any inkling that it was going to happen it would be stupid to wait till that moment to start moving them. @JanusBahsJacquet As for jogging at 8 mph over distance, you have to be running 6 days a week to sustain it but it's totally doable, I used to do it for 10-13 miles a day. Also it's been established that he can use the speed-force to affect the momentum/inertia of others so that he doesn't kill them when moving/picking them up at those speeds. – Ryan Aug 10 '16 at 21:44

Flash doesn't really work like that. The more he trains, the faster he is capable of moving.

For example, when he first gained his powers, he wasn't able to use the Speed Force to moderate his speed properly, and accidentaly reached escape velocity:

Flash running

Other times, he's capable of jogging or walking across a battlefield within a few microseconds, which indicates massively hypersonic speeds:

Microsecond Flash

During Convergence Speed Force #2, Flash was also capable of accelerating his foot to C fractional speeds when fighting an alternate universe Wonder Woman.

enter image description here

In other words, Flash seems capable of casually hypersonic/relativistic speeds.

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