Portal: Watch Knowledge

A chronometer certification is the testing and official authentication of high-precision watches.

High-class watches show only small rate deviations as a function of position and temperature. If the position and temperature dependent deviations are particularly small, the watch is a chronometer, an denomination for particularly accurate watches.

Various organizations test movements, at the request of their manufacturers, through extensive rate measurements, whether they are consistent with the chronometer requirements. After having passed the examination a tested movement receives an offical certification. In most cases the watch manufacturer will print the term Chronometer on the dial as a marketing measure.

In Switzerland since 1979 the chronometer certification is performed by the COSC (Contrôle Officiel Suisse des Chronomètres). The COSC is an independent and non-profit organization, which is neither controlled by the Swiss government nor supported financially. The watch movements are examined in the test laboratories in Geneva, Le Locle and Biel …

>>> more >>>