Water resistance in watches – explanation & water pressure chart

The water resistance of watches is often a source of misunderstanding – many watch wearers believe that "30m water resistant" means they can dive to a depth of 30 meters with the watch. However, this is incorrect. In this article, we explain what the BAR and ATM ratings actually mean, what level of water contact your watch can withstand, and what you should absolutely keep in mind.

BAR and ATM information on watches

All specifications regarding the water resistance of watches are made according to DIN 8310. Water resistance on watches can be indicated in meters, BAR, or ATM.

• 1 ATM = 1.01325 bar
• 1 bar = approx. 10 m water depth

Important: A watch labeled "30 m water resistant" (3 bar) does not mean you can dive to a depth of 30 meters with it. This rating only describes the test pressure under laboratory conditions. In practice, such a watch will only withstand splashes of water .

What does "waterproof to 3 bar" mean for a watch?

"Waterproof to 3 bar" means that the watch can withstand a test pressure of 3 bar – theoretically equivalent to a depth of 30 meters. In reality, however, the watch is only protected against splashes of water. It is not suitable for showering, swimming, or diving.

Is a watch rated at 1 ATM waterproof?

No. A watch with a 1 ATM rating or without a more precise specification is not waterproof . It should not be worn while washing your hands or in the rain, as even moisture or splashes of water can cause damage.

Can I shower with a watch that has a 3 bar water resistance rating?

No. A 3 bar water-resistant watch is not suitable for showering or swimming. Showering creates additional water pressure and significant temperature differences, which put stress on the seals. This can cause water to enter the watch movement.

Water pressure chart for watches

• 3 bar / 30 m – splash-proof only (handwashing, rain)
• 5 bar / 50 m – Showers, light water contact
• 10 bar / 100 m – Swimming, snorkeling
• 20 bar / 200 m – Recreational diving
• Diver's Watch (ISO 6425) – professional diving operations

Important care instructions for your waterproof watch

• Rinse the watch with tap water after contact with salt water .
• The crown and pushers must always be tightly closed.
• Never operate the buttons underwater.
• Have the seals checked and replaced once a year, especially before the bathing season.

Conclusion

The BAR or ATM markings on your watch give you an idea of ​​how much water contact your watch can withstand. However, they are not a true diving depth rating. With the right understanding, you can avoid damage, extend the lifespan of your watch, and use it optimally in everyday life or during sports.