20 ATM Watch Explained! What It Is, And What It Can Do!

In this article, I will be talking about the 20 ATM watch. Here I will explain what that means, what the applications are, and where you can get one. The first thing we need to do here is to get a very brief and accurate definition of a 20 ATM watch, so here it is.

A 20 ATM watch is a watch that can withstand the pressure up to a depth of 200 meters underwater. So what exactly does this mean? Well, read on and we will get into much further detail about this topic.

Now that we have the short answer to what a 20 ATM watch is, we can get into a more in depth explanation.

What Does ATM Mean On A Watch?

what does 20 atm mean on a watch

First of all, the abbreviation “ATM” really stands for “atmospheres”. Basically an atmosphere is a measure of the amount pressure a watch can take below sea level.

The starting point for measuring ATM is the pressure at sea level, which would be 1 ATM. That 1 ATM is the equivalent of 10 meters of pressure. This is the air pressure of earth’s atmosphere by itself. Everything after that would be the pressure below sea level, or underwater. This is what distinguishes “atmospheres” as far as measuring pressure.

The Truth About ATM

So, 1 ATM is the starting point, and that represents 10 meters of pressure, then every 10 meters below sea level adds 1 ATM to that number. Therefore 10 meters below sea level would be 2 ATM, 20 meters would be 3 ATM, and so on. But this is not how watch companies measure ATM.

If a watch is rated 3 ATM, then they mean that it can withstand a depth of 30 meters. 5 ATM would mean 50 meters, and so forth. So why the discrepancy between the technically accurate versions of ATM, and the watch company versions?

I would assume it is just a way to simplify things for consumers. But even their definitions of water resistance can be misleading. For instance, how they measure this resistance is not the same as actual practical application. I will explain this further in the next part.

How ATM Is Measured In Watches

A watch’s ATM number is not measured in the way you might think. For example, say a watch is rated 10ATM. It is not that the watch is brought to a depth of 100 meters underwater. Rather it is sprayed with water jets that have the equivalent force of the pressure of a 100 meter depth.

So in actual application, if you took this watch down to a depth of 100 meters, it could theoretically withstand this depth. But, this doesn’t account for additional pressure put on the watch through the act of swimming, or motion.

Secondly, at that actual depth underwater, the watch would be exposed to that pressure from all angles. So for what length of time could a watch last at that depth?

There are some general guidelines concerning A watch’s ATM number, and its usage. Here’s a short list covering the recommendations based on ATM.

General ATM Guidelines

  • 3-5 ATM: Can withstand splashes of water, rain, and maybe even showering, but shouldn’t be fully submerged in water.
  • 10 ATM: Can handle swimming, snorkeling, and maybe even scuba diving.
  • 20 ATM: Can handle deep diving.
  • 30 ATM and up: Suitable for professional diving, or saturation diving.

Ok, so with those explanations out of the way, we can look at the potential applications of a 20 ATM Watch.

Applications Of A 20 ATM Watch

applications of a 20 atm watch

As you can see, a watch that is rated 20 ATM is suitable for various aquatic activities. With a 20 ATM watch you can swim with it, shower with it, and scuba dive with it without having to worry about receiving any water damage to the watch.

As a matter of fact, a water resistance of a minimum of 100 meters could be considered a dive watch if it meets the other criteria necessary to be labeled as such. Many diving enthusiasts just skip the 100 meter minimum, and recommend a watch with 200 meters of water resistance. This would make the 20 ATM watch a likely candidate for a diving watch.

Keep in mind though that just because a watch is rated 20 ATM, that doesn’t mean it is a certified diving watch. It must still meet all of the other stringent criteria to get that title. Second, not every watch that meets all of the standards of a dive watch is going to necessarily be labeled a “dive watch”.

So what you are going to have to do in the cases when you are not sure if a watch can be used as a dive watch is to either check the user manual, or contact the manufacturer.

In the next part, we will show some examples of 20 ATM watches.

Examples of 20 ATM Watches

These are some popular 20 ATM watches we have previously covered.

G-Shock Wr20Bar

This is a G-Shock model watch, so you know it is built tough!

This watch features an ana-digi display. It has led backlighting to allow for visibility in the dark. You can set it to multiple time zones. And lastly, one cool feature with this one is a built in water pressure gauge.

Check out our full review of this watch here

Invicta Pro Diver

Whether you love or hate Invicta, the fact remains that this is a pretty decent dive watch. This watch has that luxury styled Rolex Submariner look to it.

The dial window is made from Invicta’s “Flame Fusion” mineral crystal. There is also a date window conveniently located at the 3 o’clock position. It has luminous hands and markers to help with visibility in dark areas. Also, the unidirectional rotating bezel will help you to keep up with dive times.

Check out our full review of this watch here

Orient Ray II

The last one we’ll look at here is the Orient Ray II. This is another diving styled watch.

This one also has a date window at the 3 o’clock position. Additionally, it has luminous hands and markers to help you to see the watch in the dark.

And like most diving watches, there is a unidirectional rotating bezel to keep track of your dive times. Lastly, this one has a 40 hour power reserve which allows it to maintain a degree of accuracy when not in use.

Check out our full review of this watch here


So based on all of the information here, we can conclude that if you are into aquatic adventures, a 20 ATM should be suitable for your needs. You can find watches with greater water resistance than that, however, you will usually be spending more money for those higher ATM watches.

And as we saw before, watches in the higher ATM ratings such as 30 ATM, are more geared towards professional diving applications. Therefore, this level of water resistance wouldn’t even be necessary for most people. For the majority of people, 20 ATM should be more than enough water resistance for a watch.

That concludes our look into 20 ATM watches. I hope that you have enjoyed this article, and that the information contained within it has been helpful. If you would like to read some more of our other interesting and informative articles, then you can do so here

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