The official laboratories (OL) of the COSC verify some 1.8 million mechanical and quartz timekeeping instruments annually. The COSC is now the only organisation in the world able to handle such a volume of pieces. Each certified chronometer is unique, identified by a number engraved on its movement and a certificate number issued by the COSC.

Guarantor of traditional precision Swiss watchmaking.

The creation of the COSC

Founded in 1973 and based in La Chaux-de-Fonds, the Official Swiss Chronometer Testing Institute (COSC) is a not-for-profit organisation recognised as serving the public interest, dedicated to Swiss watchmaking. Created by five watchmaking cantons (Bern, Geneva, Neuchâtel, Soleure and Vaud), as well as by the Federation of the Swiss Watch Industry (FH), it brings together a number of laboratories that were originally founded as independent institutions in the late 19th century.

A traditional label

Its principal aim is to measure and verify the precision of the watch movements and finished watches entrusted to it by manufacturers, in order to award them the official certified chronometer title.

The COSC’s human resources and the capabilities of its various premises enable the organisation to respond to all requests from the Swiss watch industry in terms of certification and chronometric controls.

The certified "chronometer” title, certifying the high level of precision and uniqueness of timekeeping instruments, is a guarantee of extreme quality, as well as the know-how applied throughout the production process. In the marketplace, it offers added value that enables beneficiaries to stand out from their competitors.

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Statistics and reliability

The COSC tests are carried out with absolute rigour:

  • The chronometric certification of wristwatches with a balance spring is based on 7 criteria set by the ISO 3159 standard, all of which must be fully met.
  • The chronometric certification of quartz watches, mechanical pocket watches or mechanical fixed timekeeping devices is based on internal requirements inspired by ISO 3159, but adapted to the specificities of the instruments.
  • Each piece examined daily for 14 to 20 days, depending on the type of instrument.
  • The certificate means that ALL the instruments entrusted to us are handled by agents of the COSC, a neutral and independent body.

The figures show a boom in COSC activity, with certifications seeing a significant increase.

  • 200,000 certificates in 1976
  • 1 million in 2000
  • between 1.6 and 1.8 million in recent years

Proof of the very high value to which the COSC "chronometer" certificate attests: only about 6% of Swiss watches exported have this status. (Source: Federation of the Swiss Watch Industry FH).