COSC Chronometer Certification

The seal of the Official Swiss Chronometer Testing Institute is considered worldwide to be one of the most prestigious honours in terms of precision.



The highly-precise movement on this timepiece has been officially certified as a chronometer by the independent testing institute COSC. Quality of this calibre speaks for itself.
All Certina chronometers therefore have an extended warranty of three years in total from the date of purchase.


Please enter the number several digits long, which is right at the bottom of your watch's chronometer certificate:

cosc - certina

the cosc

The renowned Official Swiss Chronometer Testing Institute (“Contrôle Officiel Suisse des Chronomètres”, or COSC) was founded in 1973 and is based in La Chaux-de-Fonds, Switzerland. It is an independent public institution serving the Swiss art of watchmaking. Its strict criteria are considered the standard for evaluating the precision of modern wristwatches – whether equipped with mechanical or quartz movements.

Quartz chronometers

COSC Certification is considered worldwide to be the epitome of precision. All quartz movements presented here are subjected to strict tests at a variety of temperatures. The maximum permissible rate deviation at 23°C is +/- 0.07 seconds per day; at 8°C and 38°C the tolerances are +/- 0.2 seconds; Precidrive™ movements overcome these hurdles easily.


Automatic chronometers

The demands placed by the COSC on modern timekeeping are very high. Automatic (self-winding) watches are tested here for 15 days at three different temperatures and in different positions; their rate deviations are measured and recorded scrupulously. In order to obtain the coveted “Chronometer” title the rate precision of a movement must fall within the range of -4/+6 seconds per day.