Many people mistakenly believe that a watch labeled 100 meters can actually be used for diving to that depth. This is entirely inaccurate. The ATM, BAR, and meter ratings on the watch represent test pressure or equivalent pressure under standard conditions, not a reliable, all-around diving depth.
Therefore, understanding water resistance ratings in watches is a crucial step before choosing any model, especially if the watch is intended for rain, swimming, or even diving. Here, we'll explain the meaning of each ATM rating and the practical difference between water resistance up to 30 meters and higher, to help you choose a suitable watch for swimming or any other water activity that suits your daily use. It's important to note that knowing the rating alone is not enough; you should consult the manufacturer's instructions for each model.
What do water resistance ratings mean in watches?
Water resistance ratings in watches are among the most important criteria that help determine how well a watch can handle water and humidity, and they are usually written in different units that may look similar but are not exactly the same.
Meaning of ATM, BAR, and Meters
The abbreviation ATM refers to the unit of atmospheric pressure, which is the most common unit used to express water resistance in watches.
BAR is another unit for measuring pressure, sometimes used instead of or in parallel with ATM.
On the other hand, the number of meters is used to express an approximate equivalent pressure, not an actual depth to which one can dive.
- ATM: A unit for measuring atmospheric pressure used to indicate the level of water resistance.
- BAR: A similar pressure unit sometimes used as an alternative to an ATM.
- Meters: A number that expresses an approximate equivalent pressure, not an actual depth of use.
How are pressure units related to water depth?
In common approximate conversions, 1 atm or approximately 1 bar is roughly equivalent to the pressure of a 10-meter-high water column under still conditions. Based on this approximation, the relationship between units and depths is as follows:
- 3 ATM: corresponds to approximately 30 meters of equivalent pressure.
- 5 ATM: corresponds to approximately 50 meters of equivalent pressure.
- 10 ATM: corresponds to approximately 100 meters of equivalent pressure.
According to the International Organization for Standardization (ISO), a rating such as 30 meters represents the test pressure or its equivalent, and is not a guarantee that the watch can actually be used at a depth of 30 meters underwater. Therefore, refer to the manufacturer's instructions for the specific model for actual use.
These numbers help you understand the level of testing the watch has undergone in general, and determine whether showering, swimming, or diving is allowed, as each use case requires a different level of protection according to the number mentioned on the watch.
Meanings of the 3, 5, 10 and 20 ATM ratings
Watch manufacturers differ in defining what is actually possible at each water resistance rating, meaning the following classifications are approximate guidelines. The watch's manual remains the most accurate reference, as variations between models can affect permissible uses even at the same rating.
What is a suitable 3 ATM rating?
A rating of 3 ATM, 3 BAR, or 30 meters is relatively low among water resistance ratings. This type of watch is more suitable for limited water exposure than intensive use.
- Handwashing: The watch can be worn without worrying about passing water splashes.
- Light drizzle: The watch can withstand some light raindrops without problem.
- Swimming or immersion: A splash-resistant watch with this rating is not suitable for them.
What are the usage limits of a 5 ATM watch?
Water resistance of 5 ATM, 5 BAR, or 50 meters indicates a higher test pressure than the previous rating, and this does not make it suitable for showering or swimming.
- Daily use: Withstands greater water exposure than 3 ATM class.
- Bathing or swimming: This is not a general rule for this classification.
- Special cases: Some models allow light surface swimming if their instructions explicitly state so.
When is a 10 ATM rating appropriate?
A rating of 10 ATM, 10 BAR, or 100 meters opens up wider possibilities for water use, within clear limits.
- Swimming: The watch is suitable for this activity according to its design and the manufacturer's instructions.
- Light water activities: Some models allow them in this category.
- Diving with equipment: This number does not necessarily mean that the watch is dedicated to this activity.
What does a 20 ATM rating mean?
A rating of 20 ATM, 20 BAR or 200 meters is associated with more demanding water activities, provided that the model is specifically designed and advertised for that purpose.
- Intense water activities: The watch is suitable if its instructions mention this use.
- Diving: The depth number alone does not constitute permission to practice it.
- Model verification: Referring to the watch's own instructions remains essential before any serious water activity.
Is the meter count sufficient for a diving clock?
A meter rating or a BAR rating of 10 or higher does not automatically classify a watch as a standard dive watch. A dedicated dive watch has additional specifications beyond the standard water resistance rating for everyday use, so distinguishing between the two is crucial before approving any watch for actual diving activities.
Why don't meters reflect actual usage depth?
Water resistance ratings for watches are measured under controlled, static test conditions, whereas during actual use, the wrist is subjected to sudden changes in pressure, continuous movement, and water jets. The water resistance rating on the watch, calculated in meters, reflects a specific test result, not a number that accurately represents all varying usage scenarios.
The difference between test pressure and water movement
Water resistance testing is conducted in a static environment under a constant, precisely calculated pressure. In real-world use, continuous wrist movement or direct contact with water increases the pressure on the watch differently than in a static environment. This difference between laboratory and real-life conditions is what makes the stated rating a general indicator of the level of protection, not a precise measurement for every situation.
How do the clock's position and temperature affect it?
Changes in water temperature affect the efficiency of the internal seals and the crown's response, both of which are crucial in preventing water from entering the watch. Furthermore, the condition of the seals themselves, in terms of their integrity and the extent of wear over time, directly impacts the watch's actual level of protection.
Therefore, the water resistance rating is viewed as an indicator that is linked to additional factors that determine the actual level of protection:
- Temperature: Changes in water temperature affect the performance of seals and the level of leakage protection.
- Condition of seals and crown: Corrosion or damage to these parts reduces the effectiveness of water resistance over time.
- Movement and impulse: Sudden movement or water impact on the clock raises the actual pressure compared to static test conditions.
According to ISO 22810:2010 standard for requirements and methods of testing water resistance in watches, actual usage conditions differ from the approved test conditions, and the degree of protection is affected by movement, water jet, heat, and the condition of the seals. The actual result varies from watch to watch depending on these factors.
Water resistance standards and diving watches
When discussing water resistance ratings in watches, it is necessary to consider the international standards that determine how this property is tested and classified, as they are the deciding factor between a watch intended for everyday use and a watch specifically designed for diving.
What is the role of the ISO 22810 standard?
The ISO 22810:2010 standard specifies the requirements and methods for testing water resistance in watches, and also defines the markings that can be placed on them to indicate this property. This standard covers watches intended for everyday use, including some minor water exposure such as splashes or washing.
How does the ISO 6425 standard differ?
ISO 6425 differs radically from its predecessor in terms of purpose and application:
- ISO 22810: Relating to water-resistant watches intended for normal everyday use.
- ISO 6425: Concerns dive watches designed for underwater use with full diving equipment.
This distinction is important because a watch designed according to the first standard is not suitable for actual diving, even if it has a high depth rating.
What does the term "water-resistant" mean?
When a watch is labeled "water resistant," it does not mean that it is designed for diving. The depth number mentioned on the watch, such as 100 meters or 200 meters, does not prove that it meets the requirements of specialized diving watches.
The Federation of the Swiss Watch Industry explains that a watch described as water-resistant must meet ISO 22810 or an equivalent Swiss standard, and that approved tests measure its ability to withstand a specific pressure under constant standard conditions.
Therefore, a depth rating on a watch does not guarantee it is rated for diving conditions using diving equipment. Check the model specifications and manufacturer's instructions instead of relying solely on the depth rating to determine a watch's suitability for diving.
Steps to choosing a watch that suits your water activity
Before choosing a watch, determine the type of activity it will actually be used for. Water resistance ratings vary among watches, and the protection you need will differ depending on the type of water exposure.
- Exposure to rain and spray: Only a basic level of protection is needed.
- Handwashing: Requires the ability to withstand frequent and rapid contact with water.
- Surface swimming: requires a higher level of protection that can withstand full immersion and movement in the water.
- Diving: requires a classification specifically for this activity, not just a high resistance number.
Check the instructions for your specific model.
Don't rely on general terms like "water-resistant" or "water-proof" when choosing a watch. Check the manufacturer's instructions for each specific model to find out what activities are actually permitted with that watch. Each model has different details, even if they look similar.
Avoid common usage assumptions
There are common assumptions that can actually damage your watch if relied upon without verification. Always consult the manufacturer's instructions directly for any potential use, rather than relying on general, fixed rules.
- Do not assume that a 5 ATM rating automatically allows swimming or showering.
- Do not assume that a 10 ATM rating makes the watch suitable for diving.
- Pay attention to the condition of the watch: periodically check the seals and crown, as damage to them reduces the actual level of protection.
- Follow the care and maintenance instructions specified by the manufacturer to maintain the resistance's efficiency over time.
When searching for an answer to a question like "Can I swim with a 5 ATM watch?" or "How do I choose a water-resistant watch?", remember that the rating should be read along with the manufacturer's instructions for each model to determine the actual permitted use.
Selected products from Cardial
In addition to identifying the water resistance levels of the watches, we present two models from the Cardial collection to suit different tastes.
Apex watch | Cardial brand
The Apex watch by Cardial is a men's timepiece with a modern, sporty design and clean, geometric lines. It features a silver case, a dark dial with purple accents, white hands and markers, and a textured rubber strap. The side of the case has blue buttons, and the Cardial logo is prominently displayed on the dial. The watch is available in two colors: navy and gray.
Cardinal brand watch
The Durra watch is a women's oval-shaped timepiece that blends classic style with modern touches. Its bezel is adorned with crystal stones, and its pearly pink dial features simple hands. It is paired with a metal bracelet featuring a wavy pattern. The watch is powered by a quartz movement and battery.
The Dorra watch is available in three colors: rose gold, gold, and silver, to suit different everyday looks and occasions.
Frequently asked questions about water resistance ratings in watches
What types of water-resistant watches are there?
Watches vary according to their water resistance rating and usage instructions. Some are designed for everyday use and light water activities, while others are diving watches that meet specific requirements such as the ISO 6425 standard issued by the International Organization for Standardization.
How do I know if my watch is waterproof?
Check the rating printed on the watch itself or in its user manual to determine its water resistance level. Then, consult the model's instructions to find out which activities are actually permitted, such as swimming, showering, or diving. Do not rely solely on the rating and test the watch by submerging it directly without first checking its instructions.
What does 5atm water resistance mean?
This rating means the watch is designed to withstand a pressure of approximately 5 ATM, which theoretically equates to about 50 meters underwater under static conditions. However, this does not guarantee safe swimming or diving to this depth; the rating is a theoretical measurement and not a practical guarantee for use under varying pressures or temperatures.
Water resistance ratings on watches describe the pressure a watch can withstand during testing, but they don't necessarily mean it can be used at depths of that pressure. Carefully reading the model's instructions and distinguishing between an everyday watch and a dive watch designed for water activities will help you choose the right watch for the specific activity you'll be using it for.