20 bar is a measure of pressure, and for water resistance ratings it corresponds to an equivalent static depth of about 200 meters. However, this does not mean real-world use at exactly that depth is guaranteed.
Pressure and depth
- In watch and diving contexts, 1 bar (or 1 atm) is treated as roughly equal to 10 meters of water depth, so 20 bar ≈ 200 meters or about 660 feet of water.
- This is a laboratory, static-pressure conversion; it assumes calm water and no extra forces from movement, temperature changes, or impacts.
Practical meaning for watches
- A 20 bar (or 20 ATM) water‑resistance rating on a watch generally means it is suitable for swimming, snorkeling, and recreational scuba diving, and is often described as equivalent to a 200 m dive watch rating.
- Despite the 200 m figure, such ratings are usually not intended for very deep or professional saturation diving, and regular maintenance of seals is needed to preserve that resistance over time.
Quick reference table
Rating (bar/ATM)| Approx. depth (m)| Approx. depth (ft)| Typical use case
---|---|---|---
1 bar / 1 ATM| 10 m| 33 ft| Splash resistant only 2
10 bar / 10 ATM| 100 m| 330 ft| Swimming, snorkeling 27
20 bar / 20 ATM| 200 m| 660 ft| Swimming, surfing, recreational scuba diving
126
