WR 50M / 5 Bar Marking — What This Mark Means

A 50M water resistance rating means the watch was tested to withstand 5 bar of static pressure in a laboratory, under the conditions of the ISO 22810 standard for water-resistant watches. In practice, this provides protection against splashes, rain, and brief accidental water contact, and 50m is the typical rating for dress watches, field watches, and everyday fashion watches.

The gap between the number and real-world use is the key point. The test applies static pressure to a new watch with fresh gaskets; it says nothing about years of gasket aging, hot water, soap, or an accidentally pulled crown. Industry guidance therefore treats 50m as the threshold where a watch survives daily life around water, not in it.

The rating is printed or engraved on the case back, typically as "WATER RESIST 50M," "WR50," "5 BAR," "W.R. 5ATM," or "WATER RESISTANT 165FT." Some brands, notably Casio, also print "WATER RESIST" on the dial or case front.

On dressier watches the marking may be small and confined to the case back's outer ring, alongside the steel and model markings.

The same rating appears in multiple formats: 50M, 5 BAR, 5 ATM, and 165 feet all describe the same test pressure. Watches at this level almost always use push-pull rather than screw-down crowns.

Era matters when reading older case backs. Before regulators restricted the term in the 1960s, many watches were marked "waterproof"; a vintage "waterproof" watch should be treated with more caution than a modern 50m piece, since its gaskets are decades old.

Despite saying "50 meters," this rating does not mean you can safely take the watch 50 meters underwater, and most guidance recommends against swimming with it at all. The figure is a static laboratory pressure, and gasket degradation over time further reduces effective resistance.

Hot showers and saunas are a separate hazard often overlooked: heat can distort seals and draw moisture inside as the watch cools, regardless of the rating.

Treat a 50M-rated watch as splash-resistant only: hand washing, rain, and accidental contact are fine, but avoid swimming, showering, and submersion. If the watch gets wet regularly, have the gaskets checked roughly annually.

If you want a watch for swimming, look for at least 100m (10 bar); for diving, 200m. See the WR 100M and WR 200M guides for those ratings.