For most people, they think the terms waterproof and water resistant are used interchangeably. Often many manufacturers do use them as such, but the terms are very different.

Waterproof, as you would imagine, means that a device is completely impervious to water. You could take it in the shower or snorkel with it and it would still keep working as it normally world providing you don’t go past a certain depth.

Water resistant, however, means that you can splash it while washing your hands or get hit by a surprise rain storm and the world isn’t going to end. However, if you submerge it in water for longer than a set period of time, you are going to find a fitness tracker that has stopped tracking.

The problem is that companies don’t always make a clear distinction between waterproof and water resistant. However, thanks to some handy water exposure rating systems, most consumers can figure out for themselves whether a fitness tracker is waterproof or just water resistant.

The Difference Between IPX and ATM Water Ratings

Even if manufacturers aren’t excessively clear on whether their product is waterproof of just water resistant, there is one sure way to figure it out. You just look at the rating. Water resistant products use the IPX scale that covers how much water exposure a product can handle. The ratings run as follows:

  • IPX-0 offers no protection against water whatsoever.
  • IPX-1 protects against dripping from above for up to 10 minutes.
  • IPX-2 protects against dripping from any direction for up to 10 minutes.
  • IPX-3 protects against spraying water from any direction for up to five minutes.
  • IPX-4 offers protection from splashes from any direction for at least five minutes.
  • IPX-5 protects from large sprays, 12.5 liters per minute, from any direction for up to three minutes.
  • IPX-6 offers protection for even larger sprays, 100 liters per minute, from any direction for up to three minutes.
  • IPX-7 allows protection against complete submersion in up to one meter of water for 30 minutes.
  • IPX-8 is the highest grade of water resistance and its specifications are wholly dependent on the manufacturer. If they have tested it in five meters of water and it works for up to 30 minutes, then its IPX-8 rating would be five meters for 30 minutes.

Alternatively, if you are working with true waterproof products, they don’t need an IPX rating, because they can be fully submerged in water. Typically, waterproof products will have an IPX7 or IPX8 rating, because it is a system that more people are familiar with.

However, what you really want to look for is an ATM rating. ATM measures how deep you can expose a device. Essentially, it tells you how much water pressure a fitness tracker can endure. The ATM scale is as such:

  • 1 ATM means a device can withstand a depth of 10 meters
  • 3 ATM means a device can withstand depths of 30 meters
  • 5 ATM means a device can withstand depths of 50 meters
  • 10 ATM means a device can withstand depths of 100 meters

Unlike the IPX system, there are ratings in between the above. You can have an ATM rating of seven, nine, or anything in between. Just add a zero on the end and that is how many meters of water it can endure before the pressure starts to shut the tracker down. Unless you are an avid scuba diver, you won’t ever need more than an ATM of 5.

How Fitness Trackers Make a Product Waterproof

When it comes to both waterproofing and water resistance, it is all about properly sealing the sensitive parts. You know, the ones that conduct electricity. A little water combined with power from a battery won’t usually give you a shock, but it will completely short out your fitness tracker.

For true waterproof fitness trackers, the idea is to fully seal off every nook and cranny that could let water get into the inner workings. This means that the charging ports are sealed by some widget that you need to pry open when charging time comes and the whole package will like be a little blockier due to the extra reinforcement.

Water resistant products, on the other hand, are a little more laissez-faire about waterproofing. The higher the IPX rating, the more you will notice the sealing. Low IPX rated products will likely not have features like a flap to cover the charging port, and if they do, it remains relatively easy to open. The idea is that the water with evaporate or be dried off before it has time to fully permeate all the fitness tracker’s sensitive bits.

So why not waterproof every fitness tracker? Well, typically companies will at least sweat-proof a product, but going the extra mile to full waterproofing is just extra cost to the manufacturer. Unless the fitness tracker comes with swim tracking, most manufacturers don’t really see a point.