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  2. How to
  3. Automatic movement accuracy

Automatic movement accuracy

An automatic – self-winding – watch is a complex system of gears and bearings. Watch manufacturers are constantly developing their watches and are trying to achieve the highest level of accuracy. However, you will notice that an automatic watch will start to run a few minutes behind or ahead after about a week. Fortunately, this does not mean that your watch is broken; most automatic watches, even the most accurate Swiss watches (COSC) have a margin of accuracy of a few seconds per day. We recommend that you reset your watch to the correct time once a week at a fixed time. 

The table below shows the maximum daily deviation of some popular and frequently used automatic movements. 

How to read the table? 

The table shows, for example, -/+12-30 sec pd The first number is the maximum number of seconds per day that the watch can run behind. The second number is the maximum number of seconds per day that the watch can run ahead. 

Some movements are made in different versions (standard, extended, premium and COSC). The standard deviation of these is stated separately. 

Swiss movements:

 ETA Sellita Ronda
 28242892SW200SW500R150
Standard-/+12-30 sec pdNA-/+ 12-30 sec pdNA-/+ 12-30 sec pd
Special-/+ 7-20 sec pd-/+ 5-20 sec pd-/+ 7-20 sec pd-/+ 5-20 sec pdNA
Premium-/+ 4-15 sec pd-/+ 4-15 sec pd-/+ 4-15 sec pd-/+ 4-15 sec pdNA
Chronometer/COSC-/+ 4-6 sec pd-/+ 4-6 sec pd-/+ 4-6 sec pd-/+ 4-6 sec pdNA

Other popular automatic movements:

Miyota  Orient 
821590156T33F6922F6724
-/+ 20-40 sec pd-/+ 10-30 sec pd-/+ 20-40 sec pd-/+ 15-25 sec pd-/+ 15-25 sec pd
     
Seiko  Seiko Instruments 
4R34 / 4R36 / 4R377S26 / 7S366R35 (replaced 6R15)NH35 
-/+ 35-45 sec pdReplaced by 4R36-/+ 15-25 sec pd-/+ 20-40 sec pd 

How do I know which movement is in my watch? 

The user manual for your watch will tell you which movement is in your watch. The standard deviation is usually also stated there. 

I don't have a user manual for my watch 

If you no longer have a user manual for your watch, type the model number of your watch into our search bar.

screenshot website
screenshot website
Scroll and click on “View all specifications”. Under Movement information you will find the movement number and you can download the user manual of your watch (if available).

The deviation of my watch is (much) greater than the standard deviation 

If the deviation of your watch is (much) greater than the standard deviation, the movement may need to be adjusted or serviced. In that case, follow our procedure for returning a product for repair.

I can't find my watch on this site 

Despite the fact that there are over 350,000 listed in our archive, there is a chance that you cannot find your watch on our site. In that case, we advise you to contact the manufacturer of your watch. Another good source of information about movements is the website https://calibercorner.com/

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