Today, Feb 12, it finally became official what the new, optional and additional certification from COSC will demand from the watch brands. But first a brief recap: COSC has been around since 1973, and the ISO standards that define what a chronometer should be have been around since the beginning of 1976. And the daily rate of –4+6 seconds precision that defines a COSC Certified Chronometer, will remain. But as of today, COSC also offers an even tougher classification, with pilot tests starting in March. The full-on tests will be offered from the fall of 2026.
“The current standard is already challenging enough, and with the new standard called COSC Excellence Chronometer, we are trying to positively challenge the brands in reaching higher standards. This is part of our mission, said COSC President Sebastien Cretegny.
So, what are the new criteria for added excellence? In a nutshell, there are three more tests: increased accuracy, magnetic resistance and a verification of the stated power reserve. However, the first step remains the same as it has been during the last five decades: The movements are shipped to one of COSC’s three testing laboratories located close to watch manufacturers in Le Locle, St. Imier, and Biel/Bienne. Here they are tested during 15 days, ensuring precision at an average daily rate variation of –4+6 seconds, and meeting six other criteria. (These are rate variation as a function of temperature, rate resumption, greatest difference in rates, difference between rates in horizontal and vertical positions of the watch, greatest variation in rates, and mean rate variation.)
Following the fifteen days (if they are certified), the movements go back to the brand for encasing. After that, complete watches will be evaluated for another five days of grueling tests that simulate wearing the watch in real life. To get the “Excellence” added to a chronometer the complete watch be even more precise during the five-day period. -2–+4 seconds is the maximum deviation per day, and the watch must also withstand magnetic fields up to 200 gauss – much stronger than for instance tablets and household magnets.
Worth mentioning is that all movements (circa 2 million per year) and watches, both on the “standard” and Excellence level, are tested individually.
Sebastien Cretegny: “We are promoting a new standard because the industry is moving, evolving, growing, utilizing new materials, and so on. We want to be part of this development.”
The new Excellence certification can also be seen as an answer to what is happening in other countries and in the Swiss ecosystem where you have for instance METAS and Rolex certified chronometers with extremely high standards.
“Around the world other markets starting to deliver high performances. Our mission at COSC is to preserve and safeguard international standards of chronometry, and remain at the forefront of the industry – and we want to keep the barriers for Swiss Made as high as we can,” said. Mr. Cretegny.
Even though the new Excellence standard is an add-on, it will require significant work on the movement, as every second of accuracy on this level requires modifications and improvements. “We want to help our clients to become even better. To maintain the relevance of Swiss Made in the global market we need to evolve as an industry. This new certification is part of that.
