Water Resistance in Wearables: What ATM and IP Ratings Really Mean
Wearables sometimes use ATM ratings and sometimes IP ratings for water resistance — the two aren’t measuring exactly the same thing.
Published 2026-03-28 · Smart Wearables
ATM Ratings
Originally used for traditional watches, ATM (atmosphere) ratings indicate pressure resistance under controlled lab conditions — 5ATM suggests suitability for swimming, though it’s a pressure test rather than a real-world duration test.
IP Ratings
IP68, by contrast, specifies dust resistance and a specific depth/duration of submersion tested directly — increasingly the preferred rating for wearables since it’s more directly interpretable than ATM’s pressure-equivalence framing.
Marketing Implications
Whichever rating you use, avoid implying open-water or extended swimming durability beyond what the specific tested rating actually covers — a common source of warranty disputes when marketing outpaces the tested spec.
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