No, we didn’t just spell ‘chronograph’ wrong. Unlike a chronograph, which is a type of watch complication, a chronometer is essentially a stamp of approval that indicates that the watch in question is of the highest standard of accuracy. Timepieces that are certified as chronometers are those that have had their movements independently tested and verified by an official organisation and have been deemed worthy of certification.
Naturally, not just any timepiece can be a chronometer. Here’s everything you need to know about chronometer watches, as well as the best ones.
What is a chronometer?
A chronometer watch is one that has been deemed to pass official chronometer testing. Chronometer testing measures the accuracy of the movement within a watch in different positions and at different temperatures. Chronometer testing is conducted independently and is so rigorous that only a small portion of watches on the market today are certified chronometers.
Select institutions perform chronometer testing, however the most well-known is Contrôle Officiel Suisse des Chronomètres (or the Official Swiss Chronometer Testing Institute), which is often referred to as COSC. You may see some watches labelled as ‘COSC-certified’; this means the movement meets the definition of a chronometer set by the International Organization for Standardization in ISO 3159.
COSC testing sees wristwatches and pocket watches tested for 15 days; they are measured and wound each day and assessed against seven criteria: average daily rate, mean variation in rates, greatest variation in rates, the difference between rates in horizontal and vertical positions, largest variation in rates, variation in rate depending on temperature, and rate resumption. Only a watch that meets all criteria is bestowed with the COSC-certified label and is allowed to bear the word ‘chronometer’ on its dial.
The average daily rate is the criterion manufactures and horologists alike most commonly refer to; this can be -4/+6 seconds a day. However some manufactures have an even more exacting standards for its chronometers. For its Superlative Chronometer watches, Rolex only allows an average daily rate deviation of -2/+2 seconds. These timepieces are not only COSC-certified but also tested in-house by Rolex.
Related: Looking for something more simple? These field watches make the ideal daily beaters
The best chronometer watches in 2024
If accuracy is something you take seriously, you’ll want to check out the best chronometer watches on the market.
1. Parmigiani Fleurier Toric Chronomètre
The Parmigiani Fleurier Toric Chronomètre was the debut release when Michael Parmigiani first launched his brand in 1996. This iteration sees the timepiece adorned with a new slate grey spiral guilloché dial with rose gold Arabic numeral appliques. It’s powered by an in-house self-winding proprietary calibre PF441 which is COSC-certified and decorated to haute horology standards.
Price: $29,000CHF
Model: Fleurier Toric Chronomètre
Movement: calibre PF441 (automatic)
Water Resistance: 3ATM
Case Size: 40.8mm
2. Chopard Alpine Eagle 41
A reinterpretation of Karl-Friedrich Scheufele’s St Moritz design from the 1980s, the Chopard Alpine Eagle 41 is an elegant take on the stainless steel sports watch trend. It’s powered by the in-house self-winding calibre 01.01-C which beats at a frequency of 4Hz and is COSC-certified.
Price: $24,175AUD
Model: Alpine Eagle 41
Movement: calibre 01.01-C (automatic)
Water Resistance: 10ATM
Case Size: 41mm
3. Rolex Cosmograph Daytona
Both a chronograph and a chronometer, the Rolex Cosmograph Daytona is known for its racing heritage and iconic tricompax dial. Beneath the legendary façade, the timepiece is powered by the self-winding calibre 4131. The in-house movement is not only COSC-certified but meets Rolex’s own exacting ‘superlative chronometer’ standards, ensuring accuracy of -2/+2 sec/day.
Price: from $24,250AUD
Model: Cosmograph Daytona
Movement: calibre 4131 (automatic)
Water Resistance: 10ATM
Case Size: 40mm
Related: What Is A Chronograph + The Best Chronograph Watches To Buy In 2024
4. Breitling Navitimer 36
A portmanteau of the words ‘navigation’ and ‘timer’, the Breitling Navitimer has a storied history in the skies. Distinguished by its beaded slide-rule bezel, it was originally designed to aid pilots in making important calculations on the fly. It’s powered by the Breitling 17 calibre, a COSC-certified ETA or Sellita movement.
Price: from $6790AUD
Model: Navitimer 36
Movement: calibre Brietling 17/ base calibre ETA 2824-2 or Sellita SW200-1 (automatic)
Water Resistance: 3ATM
Case Size: 36mm
Related: The Best Pilot’s Watches For Every Kind Of High Flyer
5. Zenith Defy 21
Zenith is famed for its El Primero movement, which marked the first automatic chronograph movement upon its debut in 1969. The Zenith Defy 21 is powered by the El Primero 9004, which features two independent high-frequency escapements — one beating at 5Hz for timekeeping and the other at 50Hz for the chronograph function that can measure up to 1/100th of a second.
Price: $21,100AUD
Model: Defy 21
Movement: El Primero 9004 (automatic)
Water Resistance: 10ATM
Case Size: 44mm
Related: No Bones About It; These Are The Best Skeletonised Watches In 2024
6. Tudor Black Bay Fifty-Eight
The increasingly popular Tudor Black Bay Fifty-Eight exudes rugged style, with a brushed steel case and black dial and bezel. It’s powered by the in-house self-winding calibre MT5612 which is COSC-certified and boasts a power reserve of 70 hours.
Price: $5910AUD
Model: Black Bay Fifty-Eight
Movement: calibre MT5402 (automatic)
Water Resistance: 20ATM
Case Size: 38mm
FAQ
A chronograph is a type of complication, with a chronograph watch being one that has a stopwatch function. Meanwhile, a chronometer is a watch with a movement that has successfully passed official independent chronometer testing for accuracy. Some chronographs can be chronometers, however this is not a guarantor of accuracy and the two words refer to entirely different things.
The Contrôle Officiel Suisse des Chronomètres (or the Official Swiss Chronometer Testing Institute) was established in 1973 in La Chaux-de-Fonds, Switzerland and is the organisation responsible for certifying the precision and accuracy of mechanical watches. To obtain COSC certification, a watch must undergo rigorous testing over 15 days in various conditions (including different temperatures, positions, and levels of magnetism). COSC-certified watches have passed these tests and keep time with a maximum variance of -4 to +6 seconds per day.
Enjoyed this article? Why not check out our Ultimate Guide To Watches here; covering everything from the anatomy of a watch to watch styles and complications.
Words by John Deckard
