What is a Chronometer Watch?

by James Ward on April 13, 2021

Do you want your watch to tell the time accurately? This isn’t a trick question.

Some people honestly don’t care – their watch is a statement, not a timekeeping tool. But if precision is important to you, then look no further than the chronometer watch.

What Is a Chronometer Watch?

A chronometer watch is a specific type of watch whose movement (the timekeeping mechanism inside) has been certified to operate within very specific ‘tolerances’ – the amount of time it can acceptably gain or lose per day.

While a normal mechanical movement’s tolerance is +/- 20 seconds per day, a chronometer movement’s is a staggering −4/+6. When you compare this tolerance to the 86,400 seconds in a full day, that equates to a daily accuracy rate of +99.994. In other words: chronometer standards are ridiculously impressive.

These tolerances are all well and good in a laboratory-like testing environment, but they become even more impressive when applied to real life. If you’re a normal person – i.e. not buying a watch to be stored in a safe as an investment – you’ll be looking to wear your new chronometer watch. And what’s the point of a watch that doesn’t fulfil its primary purpose during everyday wear?

With the multiple tiny moving parts that create a movement subject to gravity and other physical forces, whether that’s small movements like reaching over to pick up your coffee, or opening a door, to more strenuous moments like the 50m sprint for the last train, a chronometer movement needs to operate at peak levels of precision throughout. That is why, even centuries after it was created, the chronometer watch remains one of the pinnacles of human creation. Because there’s only so much we could have achieved with a sundial.


What Does Chronometer Mean?

The term ‘chronometer’ was coined by Jeremy Thacker in 1714. Its definition derives from ancient Greek, with ‘chrono’ meaning time, and ‘meter’ meaning measure. And that’s essentially what a chronometer watch does: it measures time – very, very accurately.

Is Every Watch a Chronometer?

No, which is what makes them so very special. 

For a Swiss-made watch to become a certified chronometer – like our range of TRIBUS Chronometers – the movement needs to be sent to the Contrôle Officiel Suisse des Chronomètres (COSC). A Swiss organisation responsible for guaranteeing the accuracy of Swiss-made watches, COSC tests each movement in a number of different positions and temperatures to ensure that its timekeeping remains precise throughout.

If the movement passes these tests, then it earns chronometer status. COSC then sends each movement back to the relevant manufacturer – in our case, TRIBUS – with a certificate, displaying its results in each position. It may seem like a lot of work, but in a world where every second counts, these tests prove the chronometer to be a tool that can be relied upon, whenever, wherever.

Now, let’s imagine a different timeline where the movement hasn’t successfully negotiated its 15 days in COSC’s testing facilities. It needs to be sent back to the manufacturer that submitted it, re-regulated to more accurate levels, and then submitted again. There’s no leeway, whatsoever – and that’s because COSC was established to protect the worldwide reputation of Swiss-made watchmaking. A country synonymous with watchmaking throughout the centuries, it takes pride in its output; so much so, it created strict ‘Swiss-made’ laws documenting that 60% of production must take place within the country. COSC acts as just another safeguard of quality.

It’s also worth noting that there are many different types of movements available throughout the watchmaking industry, some featuring mechanical parts, some powered by a quartz battery. Any of these movements can be classified as a chronometer, as long as they meet those very specific timekeeping requirements required by COSC. For a mechanical watch to be classified as a chronometer watch (as per International Organization for Standardization 3159), it needs to hit that tolerance of −4/+6 seconds per day, while a quartz chronometer operates within +/-0.02 seconds per day.

Just to clear up a point of confusion: you’ll hear terms like ‘chronometer watch’ or ‘chronometer movement’ thrown around a lot. While a watch can be known as a chronometer watch, it’s the movement inside that achieves chronometer status (think similar to how everyone calls the iconic clock tower ‘Big Ben’, when this is actually the name of the bell inside).


Who Invented the Chronometer?

Jeremy Thacker may have coined the term in the 18th century, but when it comes to who invented the chronometer, the famous clockmaker John Harrison takes the honour. His creation of a ‘marine chronometer’ in 1728 solved the British parliament’s ‘longitude problem’, with a £20,000 reward offered to whoever devised a means of pinpointing a ship’s location at sea using longitude. Harrison’s problem-solving chronometer, a pocket watch named H4, could be used to help ships safely navigate long-distance journeys, remaining accurate despite being aboard a rocking vessel, alongside the various changes in pressure and temperature both faced – all whilst operating within the tolerance of +/- 2.8 seconds per day demanded by the Board of Longitude.

Today’s chronometer watches are smaller and more wearable than Harrison’s original developments, but the core challenges remain the same: they need to remain extremely accurate, wherever they are in the world, whatever they’re subjected to.


Why Do We Need Chronometer Watches?

Humankind has always needed a way to track time. It’s what ensures some kind of order to civilisation, ensuring we show up in the right place at the same time as everyone else. Timekeeping started with simple devices like sundials and hourglasses; rudimentary methods that would keep the time, but with some leeway. Fast-forward through the centuries, and as engineering progressed, so did timekeeping. Time was no longer restricted to the local church clock; mechanisms grew smaller and smaller, until the point they became portable – think pocket watches for gentlemen, and, in the 16th century, the first wristwatches. Time was now wearable. And that meant in the pursuit of accuracy, the chronometer watch was born.

What Is a Chronometer Watch Used For?

Do you like being on time to things? If you’re generally a punctual person, a chronometer watch is a good thing to have on your wrist. If you’re not, then hire a PA and chauffeur who can get you to places on time – a chronometer watch won’t solve your timekeeping problems any more than a phone that’s linked to the Atomic clock will.

But if you want bragging rights that you’re wearing a piece of precision engineering that won’t run out of battery after about 12 hours and has far more personality than any iPhone or Android, then your chronometer watch is a lasting statement.

So, speaking of statements…

Which TRIBUS Chronometer Watch Should I Choose?

When it came to creating our own range of TRIBUS chronometers, this obviously meant sending them to COSC for those 15 days of meticulous testing. That attention to detail is immediately obvious; each TRIBUS has been hand-made with care in Lugano, Switzerland, with a mix of different styles, colours and watchmaking complications that cater to an array of needs.

TRI-01 Small Second COSC

Back when John Harrison was designing and building his own chronometer watches from scratch, he probably didn’t think that 300 years later there would be watches with colour schemes like the TRI-01 Small Second COSC.

Inspired by traditional dress watches, but with vivid dial choices like salmon, yellow and teal (not forgetting equally impressive options like black and cream), the TRI-01’s modern retro visuals will stand out just about anywhere. In an era of smartwatches, the TRI-01 Small Second COSC is a watch that just looks smart.

TRI-02 GMT 3 Timezone COSC

The 1950s marked the dawn of the jet-setting age, with newly available long-distance flights making those far-flung exotic locations that little bit more accessible. The first GMT watches were created to assist pilots during these flights, allowing them to read the time at both their destination and origin simultaneously as they crossed multiple timezones.
The TRI-02 GMT 3 Timezone COSC reflects the retro stylings of that era, but with striking black and yellow visuals, it’s undoubtedly a modern watch made for modern needs.

With a combination of its adjustable 24-hour bezel and chronometer-certified GMT movement, it can read three timezones simultaneously – perfect for business and travel.  

TRI-03 Power Reserve GMT COSC

If the TRI-01 Small Second COSC introduced our modern retro aesthetic in its purest form, then the TRI-03 Power Reserve GMT COSC builds upon it whilst additional horological firepower into the mix.

Already an impressive looking watch with a clean, classical aesthetic, it then incorporates both GMT and power reserve functionality. Its suave visuals will look the part in the boardroom or on the beach, with multiple different finishes available to suit your own style.

TRI-04 Power Reserve GMT Sport COSC

The dark horse of the TRIBUS range, the TRI-04 combines stealthy visuals with the functionality of a special ‘sports’ bezel. Simply align the bezel’s triangle with the current minute when the half kicks off, and you’re good to go. Not just a useful tool for timing events, the TRI-04 also possesses GMT and power reserve complications too. It’s ready to go, whenever you are – wherever you are in the world.

Which one will you go for?

Visit our TRIBUS Chronometer range here
To learn more about the Contrôle Officiel Suisse des Chronomètres and its testing procedures, visit their website here
1 comment
by Ben on April 28, 2021

What beauties, one of the best modern watch design I’ve ever seen… BUT I’ve 16,5 cm wrists and currently wear a watch with 48mm lug-to-lug and the lugs are just not yet over my wrist, but with more it would.
Is there any change to bring out a 38m or 39mm watch with lugs under 50mm?

Further a dial, case, strap custom watch builder would be great.
My favourite would be Stainless Steel, Teal, camel-strap.

Thanks and keep on ticking!


Please note, comments must be approved before they are published