Chronograph vs. Chronometer: What’s the Difference?
Chronograph vs. Chronometer: Key Differences
A chronograph or a chronometer, what do they both mean? They both start with chrono, which means ‘time”, but they mean different things relating to a watch. One measures short periods of times while the other is a high-precision watch that is officially certified. You can also have a chronograph that is also a chronometer. Continue reading to learn more about what each of these mean.
While both chronographs and chronometers are precision timepieces, they serve very different functions. A chronograph is essentially a stopwatch — useful for timing events — whereas a chronometer is a designation for exceptional timekeeping accuracy, often certified by institutions like COSC. Notably, some watches — like certain Omega Speedmasters — are both chronometers and chronographs.
What Is A Chronograph Watch?
A chronograph is one of the most common complications found on a watch. You can read more about the history of a chronograph on our blog, but here’s what you need to know about this watch complication. The watches have pushers to start, stop and reset the time tracker, and registers to read the elapsed time. There are different types of bezels that allow you to track different things, such as a tachymeter or pulsometer. There are also many types of chronograph watches, from a classic chronograph to a flyback chronograph or a split-second chronograph. Learn more about common types of chronographs in our video.
How a Split Second Chronograph Works
Going deeper into a more advanced chronograph, a split-seconds, or rattrapante chronograph has the ability to track two intervals that start at the same time. Imagine a race where runners all start together and want to track one racer with each lap. You would be able to start the chronograph when the race begins, and then stop one of the chronograph hands at the first lap, and the second at the next. You can watch our hands-on review of the Patek Philippe 5370P where Tim Mosso showcases the split-seconds function.
Popular Chronograph Watches
- A. Lange & Sohne 1815 Rattrapante Perpetual Calendar
- Zenith Defy El Primero 21
- Vacheron Constantin Overseas Chronograph
- Omega Speedmaster
- F.P. Journe Linesport Centigraphe
What Is a Chronometer Watch?
A chronometer does not have to be a chronograph. While a chronograph measures time, a chronometer refers to an instrument (a watch) that accurately measures time. To be a chronometer, the watch must pass a variety of precision tests.
A watch is put to a number of internal and external factors once it leaves the manufacture. Gravity, humidity, water, magnetism, lubrication within the movement, and general wear and tear can all have an effect on the watch.
No watch is 100% accurate, but there are standards to which chronometer certified watches adhere to: +6/-4 seconds per day. The COSC Certification is the official Swiss chronometer testing, and it stands for Contrôle Officiel Suisse des Chronomètres.
COSC Certification: Official Swiss Testing Agency
Only watches that have gone through the COSC testing are able to have the word chronometer printed. The testing measures the movement across 15 days and multiple environments to ensure the +6/-4 seconds accuracy. The movements are put to extreme temperatures from around 46 degrees Fahrenheit to 100 degrees and set at different positions.
The COSC tests around 1.8 million watches per year, a small portion of the Swiss watch industry. Every watch that passes through the testing gets a chronometer engraving on the movement.
Does Patek Philippe Have A Chronometer?
Patek Philippe does not submit their watches to COSC certification. Instead, the brand had used the Geneva Seal for their watches, up until 2009. The Geneva Seal still rigorously tests watches, putting them through 12 stages or conditions, and produces a certification at the end. The movements are then stamped with the Geneva Seal. Cartier, Chopard, and Vacheron Constantin are among brands currently using the Geneva Seal.
Since 2009, Patek Philippe has used their own testing and seal, the Patek Philippe Seal. This can be spotted on the movement as the double P. The Patek Philippe Seal puts the watches through stricter tests than COSC. Their watches are set to a standard of -3/+2, a smaller deviance than the COSC certification.
Omega METAS Certification: In-House Chronometer Testing
Omega is a brand that takes COSC certification to the next level and performs its own in-house certification, METAS, giving the movement a dual certification. These secondary tests are performed after the movement has already been COSC certified and allow the watch to be called a Master Chronometer. There are 8 METAS tests and Omega has a digital record allowing owners to look up the testing results.
Popular Chronometer Watches
- Rolex Daytona
- Omega Seamaster Diver
- Rolex Submariner
- Breitling Aviator 8
- Tudor Black Bay Bronze
Which Is Better — Chronograph or Chronometer?
It depends on your needs. If you’re interested in a complication for timing laps, events, or functions – especially in motorsports or aviation – a chronograph is essential. If you care more about precise timekeeping and mechanical performance, a COSC-certified chronometer is ideal. For those who want both, watches like the Omega Speedmaster or Breitling Chronomat offer the best of both worlds.
Looking for a chronograph or chronometer watch of your own? Explore our current selection of chronograph watches or browse all pre-owned watches and keep an eye out for the Chronometer phrasing found on COSC certified watches.
Frequently Asked Questions
Q. What is a chronometer watch?
A. A chronometer watch is a timepiece that has passed rigorous precision tests and is certified for high accuracy, often by COSC in Switzerland.
Q. What does chronograph mean on a watch?
A. A chronograph is a stopwatch function built into a watch, allowing you to measure elapsed time with additional subdials.
Q. What is the difference between a chronometer and a chronograph?
A. A chronometer refers to accuracy certification, while a chronograph refers to a stopwatch function. A watch can be one, both, or neither.
Q. Are chronograph watches automatic?
A. Many chronograph watches are automatic, but they can also be quartz or manual-wind depending on the movement.