Chronometer certification

Chronometer certification is a standard that certifies a watch's precision and performance. Authorized by official testing institutes like the Swiss COSC (Contrôle Officiel Suisse des Chronomètres), it involves rigorous testing over several days in various positions and temperatures. Only watches that meet strict accuracy criteria—typically gaining or losing no more than a few seconds per day—earn the certification. This ensures that certified chronometers deliver reliable, high-precision timekeeping, reflecting a watch's quality and craftsmanship.