How do water resistance ratings work in watches?
Updated
by Vaer Watches
Water-resistance ratings in watches are a confusing subject because the depth rating numbers don't match real-world usage. In general, 10 ATM (100 meters depth rating) is the starting point for a watch being functionally waterproof.
Almost all men's wristwatches claim some level of water resistance rating on the case back - but what do these numbers actually mean? While 30 or 50 meters of water resistance may seem more than sufficient for a quick swim in the pool, in reality, they offer limited resistance beyond the occasional spray.
For a functionally waterproof watch (covering 99% of real-world use cases) you're going to need, at minimum, a watch rated to 100 meters (328ft) of water resistance - in the watch industry this rating is often abbreviated to 10 ATM (atmospheres) or 10 Bar.
Below is a quick summary of ATM ratings and what they mean:
- 1 ATM - Essentially no water resistance, stay away.
- 3 ATM - Covers splashes, not steam or submersion.
- 5 ATM - Handles quick submersion and showering.
- 10 ATM - Covers swimming and submersion.
- 10 ATM + Lock Crown - Functionally waterproof.
- 20 ATM - Waterproof to limits of the deep diving.
- 30 ATM - Waterproof at depths of oxygen toxicity.
- 100 ATM - Pretty much just showing off.
- Reagan Cook, Vaer Co-Founder
