A newly proposed certification standard for Swiss watches (set to debut in 2026) builds upon the established COSC chronometer certification.
Background
Since 1973, the existing Contrôle Officiel Suisse des Chronomètres (COSC) chronometer standard has required movements to be adjusted to -4/+6 seconds per day accuracy before being cased up, certifying precision, though focusing on the movement alone.
Although Super-COSC is an enhanced version of COSC designed to certify the entire assembled watch, similar to the Superlative Chronometer standards (Rolex) and the Master Chronometer standard (METAS), it will not include water resistance testing.
Super-COSC Chronometer
Semi-dynamic and Dynamic Testing: Assessing rate stability under simulated wrist movements.
Magnetic Field Resistance: Evaluating performance in moderate magnetic fields (like those from smartphones or laptops). This contrasts with higher benchmarks such as the Master Chronometer, which targets extreme levels of magnetism resistance.
Power Reserve Validation: Verifying the actual power reserve under realistic use conditions.
Temperature Variation Response: Confirming the watch’s accuracy within acceptable limits during temperature fluctuations (e.g., between indoor and outdoor environments).
Types of Chronometer Certifications
Rolex Superlative Chronometer: focuses on the fully assembled watch and includes testing for water resistance and power reserve alongside precision within a narrow rating of -2/+2 seconds per day.
METAS Master Chronometer: tests the assembled watch and includes strong anti-magnetism criteria (up to 15,000 gauss), water-resistance testing, and performance under various conditions. In addition, each watch is tested to ensure precision of 0/+5 seconds per day. (Notably, this testing has the prerequisite of being COSC certified.)
COSC Certified Chronometer: movement is tested and adjusted to -4/+6 seconds per day, before the movement is cased up. And without testing of power reserve or magnetism.
Final Thoughts
In essence, Super-COSC seeks to enhance the relevance of COSC certification for the modern watch consumer by evaluating the complete watch in real-life scenarios, adding to the growing landscape of advanced watch certification standards.
While Superlative Chronometer testing is reserved for Rolex, and currently, METAS Master Chronometer testing is only used by Omega and Tudor, Super-COSC presumably aims to be the mainstream option for chronometer testing, just as it always has been with COSC certification. To that point, COSC will now make it easier to implement testing by allowing it to be done at either COSC laboratories (located in Biel/Bienne, Le Locle, Saint-Imier) or, optionally, at the watchmaker’s facility.
How much each of the four primary Swiss testing methods (COSC, Superlative, Master Chronometer, or Super-COSC) adds to the cost of each watch is unclear. What’s abundantly clear is that consumers paying the premium for Swiss watches expect the most precise timekeeping — and these different tests ensure that at scale.
Photo by COSC.
