chronometer watches

What is a chronometer, and the best to buy

It takes 15 days of rigorous, vigorous tests for a watch to be crowned a chronometer. Here’s what the certification means, and the watches that exemplify it.

Chrono; it’s an interesting prefix. Derived from Khronos, the Greek personification of time, there are hundreds of words that plonk those six letters in front of them — from chronology to chronometry. But we’re only interested in two. And, like the word itself, they’re intrinsically buckled onto the concept of time.

Chronographs and chronometers are both watchwords for watches. But what do they mean? It’s a question commonly asked and, while a chronograph refers to a function of a watch — a complication that goes beyond the simple display of seconds, minutes and hours – a chronometer is a stamp of approval; an indication that the movement has been tested and controlled by an official organisation and deemed worthy of certification.

"A chronometer is a stamp of approval..."

It’s just what you want from a watch. And, thanks to the rigorous, vigorous testing that these certified watches undergo, not just any timepiece can call itself a chronometer. Select institutions, from the Observatoire de Besançon in France to Germany’s Glashütte Observatory carry out these tests — with the Contrôle Officiel Suisse des Chronomètres the gold standard for hair-splitting horologists.

The tests themselves examine many of a watch’s functions; from fluctuations in time rates when the watch is horizontal and vertical, to the difference in rates depending on temperature. These trials take 15 long, laborious days and, only then and only if successful, can the word ‘chronometer’ be applied to the dial. This makes the chronometer crowd a rarified group — and we at Gentleman’s Journal have even further wheedled out the best of the bunch below.

Calibre 4130: Rolex Cosmograph Daytona

Rolex Cosmograph Daytona

If you look beyond that pioneering Oysterflex bracelet, and behind the ice cool steel and black dial, you’ll find that this Rolex racing watch has quite the perpetual pedigree. Boasting a 4130 movement, this self-winding mechanical Cosmograph has been built with enhanced reliability and is a COSC-certified Swiss chronometer.

It features a Parachrom hairspring, offering greater resistance to shocks and temperature variations — and boasts additional functions including a 30-minute counter at 3 o’clock, 12-hour counter at 9 o’clock and stop seconds for precise time recording.

Rolex Cosmograph Daytona

Rolex Cosmograph Daytona

£22150

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Calibre 01.01-C: Chopard Alpine Eagle Large

Chopard Alpine Eagle Large

We can’t get enough of Chopard’s latest. Crafted from an exclusive, ultra-resistant and light-reflecting metal called Lucent Steel A223, this watch is a state-of-the-art reinterpretation of Karl-Friedrich Scheufel’s 1980 St. Moritz design for the brand — and it beats to the rhythm of a Chopard chronometer-certified movement.

Entirely developed and crafted in the Chopard watchmaking workshops, the calibre 01.01-C is a self-winding mechanical movement and has a frequency of 28,800 vibrations per hour. With a 60-hour power reserve and a stop-second function, it displays the hours, minutes, seconds and date with the precision and elegance characteristic of the storied Swiss brand.

Chopard Alpine Eagle Large

Chopard Alpine Eagle Large

£11200

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Calibre 17: Breitling Navitimer Automatic 41

Breitling Navitimer Automatic 41

A brand-new take on the Navitimer, Breitling’s steel blue timepiece effortlessly combines the historic appeal of a true icon with the sophistication of a contemporary timepiece. And, if you look past the brand’s famous circular slide rule and distinctive beaded bezel, you’ll find quite the calibre.

The Breitling 17 movement, a COSC-certified chronometer, is compact and refined — a self-winding mechanical marvel with a power reserve of 38 hours and 28,800 vibrations per hour. All contained in a 41mm stainless-steel case, it’s an elegant reinvention of legendary watch.

Breitling Navitimer Automatic 41

Breitling Navitimer Automatic 41

£3350

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Calibre MT5612: Tudor Black Bay Steel

Tudor Black Bay Steel

The famous diving watch from Tudor looks its best in this all-steel version with a brushed bezel insert. Introducing a date function to the Black Bay family, this is just one of the reasons we’re so taken by the Swiss brand’s calibre MT5612 — the jewel in Tudor’s watchmaking crown.

A self-winding mechanical movement with bidirectional rotor system, the most important feature of this revolutionary calibre is surely its power reserve; an incredibly impressive 70 hours. But it’s not all about the movement with this one — it’s also waterproof to 200 metres.

Tudor Black Bay Steel

Tudor Black Bay Steel

£2750

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Calibre 79320: IWC Pilot’s Watch

IWC Pilot’s Watch

Clearly organised and clearly desirable, it’s the highly legible dial of IWC’s Pilot’s Watch that first grabs you by the lapels of your flight jacket. But, despite the striking red stop-seconds hand, glowing luminescence and bright, clear numerals, it is the movement that really gets this one ticking.

For that, you must thank the robust calibre 79320 movement, with which it is possible to record single and aggregate times of up to 12 hours. Subdials indicate the watch is running smoothly at all times, and the movement has optimum protection against the effects of external magnetic fields in the form of a soft-iron inner case.

IWC Pilot’s Watch

IWC Pilot’s Watch

£4890

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Calibre 2385: Audemars Piguet Royal Oak

Audemars Piguet Royal Oak

It would have to be one hell of a movement to keep up with the breakneck design cues and snappy stylishness of Audemars Piguet’s Royal Oak. Just look at that signature octagonal stainless steel case, and contemporary two-tone Grande Tapisserie dial. Thankfully, this particular timepiece is also fitted with the self-winding calibre 2385; and it is an incredible movement.

At just 26.2mm across, it is a masterclass is compact engineering. Boasting a monobloc oscillating weight in 18-carat gold, the 2385 is made up of 304 parts, which click and tick together to give this Royal Oak a 40 hour power reserve, hours, minutes, small seconds and date.

Audemars Piguet Royal Oak

Audemars Piguet Royal Oak

£23700

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Want more watches that have ticked into the history books? Take a look at the IWC Mark II…

Further Reading