Chronometer (COSC certified)

A watch called Chronometer (COSC certified) is tested and certified to meet certain precision standards. In Switzerland, only watches certified by the Contrôle Officiel Suisse des Chronomètres (COSC) may use the word ‘Chronometer’ on them. So, it is always COSC certified.

Some brands like Rolex and Omega, have their own certification that even goes one or a few steps further than the ‘standard’ COSC. Although they explain what extra tests they do, we label those watches with COSC as well.

Outside Switzerland, equivalent bodies such as the Japan Chronometer Inspection Institute, have certified watches to the same internationally recognized standards.