"Certified Chronometer"
THE COSC LABEL
A guarantor of quality and excellence
Strategic, scientific, commercial challenges... The pursuit of the exact measurement of time has spanned centuries, responding to different challenges in different eras. Today, the COSC chronometric certification is the guarantor of precision for watchmaking enthusiasts and a reassurance for all watch buyers.
The chronometer: a certified title
This title is certified by a neutral official body, in accordance with the ISO 3159 standard. In Switzerland, each chronometer is certified by a unique number engraved on its movement and comes with a certificate issued by the COSC. Many brands also choose to display the “Certified Chronometer” designation directly on the watch.
The COSC certification is recognition of the brand's flawless quality system and proof that “chronometer” has been considered at every stage of research and development, from production to precision testing.
At present, there is no dedicated standard to certifying the precision of a chronograph.
Chronograph or chronometer ?
A chronograph is a complication on a watch that makes it possible to measure an interval of time. A chronometer is a high-precision watch that has been tested and certified by the COSC. This label is given to a precision timekeeping instrument set for various conditions of use (e.g.those of ISO 3159 for mechanical chronometer wristwatch).
The Certification
FAQ
What information can the buyer of a chronometer-certified watch obtain from the COSC?
None. The COSC is the repository of analytical results that belong to its customers (the watchmaking brands). It does not have the authority to disclose information to anyone other than the legitimate owners of those results. The buyer should contact the head office of the brand to which the chronometer belongs.
Is every chronometer sold with a certificate from the COSC?
No. Documents issued by the COSC are optional. It is for the brands themselves, and only them, to decide whether or not to communicate the results obtained during certification of the movement or watch by the COSC.
How long is the chronometer certification valid?
The chronometer designation can be compared to a university degree. At a given moment in life, the candidate proved, on the basis of an examination, that they have met all of the performance criteria that allowed them to merit the designation. Just as is the case for a graduate, this designation is acquired for life, even if one's performance is likely to change somewhat over time.