watch complications guide

Watch Complications 101: A Guide From The Collective

Watches and the hobby that surrounds them can be complicated to understand. There are many different brands and types of watches and many different functions performed by those watches. Heck, we even call a function or feature on a watch a “complication”, it’s like the watch gods want you to be confused. No more! In this article, we’re going to do a deep dive into watch complications to help you make sense of all the different, useful, and sometimes bizarre functions found in a mechanical watch. 


What are watch complications?

First, we need to get into what a watch complication is. In the simplest terms, a complication is any extra functionality on a watch other than just telling the time, meaning hours, minutes, and seconds. A non-complicated watch tells the time and nothing else, while a watch with a complication has additional “features” like displaying the date or another time zone. One key piece here, however, is that a complication is built into the watch movement mechanically. Things like a bezel or helium escape valve add functionality but not from a mechanical perspective, so they don’t count. 

Why are features called watch complications?

These extra features on watches are called complications because, well, they make watches more complicated. Additional information like the date being displayed on a watch requires additional parts and makes the movement more complicated to build and service for a watchmaker; thus, it is called a “complication”. Features like a chronograph or perpetual calendar are especially complicated, and some watches even combine multiple complications into one, making them exceptionally complex. The most complex of these are called Grand Complications, but we’ll get into that a bit later.

What do Watch complications do?

What a watch complication does can vary depending on the type. A chronograph, for example, is a complication that acts like a stopwatch and tracks elapsed time. A GMT tracks multiple time zones at once. Generally, complications are built to solve particular problems and help make life easier for those who frequently encounter those problems. A chronograph can be useful for an athlete who often needs to time intervals or laps in a race, while a GMT is very helpful for someone who travels a lot like a pilot. There are many different types of complications that have different purposes, but overall, they’re little mechanical problem solvers and tools to help the wearer in their day-to-day lives.


Is a tourbillon a complication?

This is a common misconception; no, a tourbillon is not a complication. It is a complicated mechanism, but it doesn’t add any additional features to the watch other than telling the time. A tourbillon is a mechanism that rotates the balance wheel, balance spring, and escapement continuously to negate the effects of gravity on a watch. The technology stems from stationary clocks and pocket watches which spent most of their lives in one position. It’s a beautiful mechanism and is undoubtedly complicated, but again it doesn’t add any functionality for the wearer. It’s also arguably not needed on a wristwatch that’s constantly in motion. So while a tourbillon—and other complex mechanical innovations—can make a watch more complicated, they are not complications per se. 

Types of Watch Complications



The chronograph is one of the more well-known complications, and is found on some of the most notable watches in history. The Rolex Daytona and Omega Speedmaster Professional, for example, are both simple chronograph watches. The best way to think about this complication is that it’s essentially a stopwatch in addition to being a regular wristwatch and allows the wearer to track and measure elapsed time. Chronographs stand out from other watches with their trademark pushers that usually flank the crown. The pusher function can vary slightly depending on the watch, but generally, one starts/stops the chronograph timing, and the other resets the timer back to zero.


You’ll also notice on many chronographs that the bezel or outer perimeter of the dial will have a calculation scale to assist in measuring things like the speed of a race car—called a tachymeter—or the pulse of a patient—called a pulsograph. These allow for more functionality than the simple tracking of time, but they’re not considered complications as they’re purely cosmetic and don’t require additional mechanical parts. There are also variations of this complication beyond just a simple chronograph. Here are some other examples of complications within the chronograph family. 

flyback chronograph allows the wearer to reset an actively running timer back to zero without stopping it, which can be helpful when timing quick intervals. Simply by pushing the reset pusher, the seconds hand will fly back to 0 and immediately start counting again. A monopusher chronograph has just one pusher—as opposed to two—that acts as the start, stop, and reset button all in one. The single pusher gives these watches an elegant style, and this complication is often found on more formal-looking timepieces.


Split-Seconds chronographs are one of the most complicated in the chronograph family. The split-seconds complication has two running seconds hands for timing and functions as multiple chronographs in one. This allows you to simultaneously keep track of an entire event as well as portions of that event. Say you want to time an entire swim race but also individual laps, start the chronograph as usual, and then once the first lap is over, push the stop pusher, this will make one hand pause, allowing you to record the time of that lap while the other hand continues recording to the total time of the race. Then press the start pusher again to make the stopped hand catch up to the other running hand, and so on and so forth through the event.


While the split-seconds chronograph is not nearly as common as a standard chronograph, it’s still much more well known than its hyper-niche sibling, the Regatta Timer. Regatta Timers are made specifically for counting down the time left before a sailboat can cross the starting line in a race. Since sailboats can’t just stay still due to being wind-powered, they continue to move around close to the starting line until they’re allowed to cross. Generally, a gunshot or some other indicator will let the racers know they have ten, then five minutes left before they can cross. With a regatta timer, one would set their watch to the proper countdown setting then activate the chronograph when the gunshot goes off. The countdown timer working in conjunction with the chronograph tells the racer how much time they have left before they can cross, allowing them to move the boat into position to cross at the best time. 

The chronograph family is a large one, so we won’t get into all the variations, but I think it’s important to note that the chronograph complication is one of the most beloved in all of watches due to its combination of utility, ease of use, and mechanical complexity. It’s not a coincidence that some of the most iconic watches ever made were chronographs.



The moon phase is one of the earliest known watch complications, and its purpose is to display—as you might have guessed—the current phase of the moon. Specifically, it shows—from the vantage point of the earth—the portion of the moon that’s lit by the sun. This is commonly done by displaying the moon—and sometimes stars and clouds for added effect—through a modified crescent-shaped window that covers the portion of the moon that the earth’s shadow hides. A moonphase movement will generally use a gear ratio based on the hour hand circling the dial twice in 24 hours. By utilizing 59 toothed moon phase disc, the hour hand can advance the moonphase one full phase per day, lining up with the approximately 29.5-day moon cycle. In my opinion, no other complication elevates a watch quite like a moonphase. They’re often beautiful to look at, and are by far the most artistically displayed complication. Some even go so far as to call the moonphase the most romantic watch complication.


Annual Calendar

The Annual Calendar is the youngest complication on this list and was invented in 1996 by Patek Philippe, first put into the reference 5035. An annual calendar displays the date while accounting for months with 30 and 31 days, only needing to be adjusted once per year in February. It’s more advanced than a simple date complication but not quite as advanced as the perpetual calendar complication meaning it hits a practicality sweet spot. Because annual calendars are less complicated than perpetual calendars, they’re cheaper, easier to get serviced, easier to use, and generally less expensive, but you don’t have to change them every other month like a date complication. 


Perpetual Calendar

Perpetual calendars represent the top of the line in calendar complications. Invented by an English horologist named Thomas Mudge, the perpetual calendar complication was first seen in the 1700s, but it was first patented and put into a wristwatch by none other than Patek Philippe. A perpetual calendar displays the date while also tracking the month of the year and whether it is a leap year. This means the only time you need to adjust the watch’s date is when the Gregorian calendar skips a leap year. The next time this will happen is in the year 2100, so it’s a set it and forget it type of complication. This is one of the most complicated watch functions, and it commands a premium on the market. Perpetual Calendar movements are often found in more formal-looking timepieces made of precious metals. Such a complicated movement needs an elevated design to match its mechanical gravitas. 



The GMT, like the chronograph, is a popular and practical complication that has an everyman quality to it. A GMT complication allows the wearer to track two different time zones—sometimes three—simultaneously using a fourth hand that rotates the dial once every 24-hours and often a bezel with a 24-hour scale. The complication is named after Greenwich Mean Time—formerly used as a universal time zone—and is meant to help frequent travelers. Though the Glycine Airman is the first watch seen with this type of two time zone mechanism, Rolex’s GMT Master is the most well-known timepiece to feature the complication.

GMT’s can be implemented in a couple of ways, and here we’ll focus on two variations, caller GMTs and true GMTs. A caller GMT utilizes a 24-hour hand which you can set independent of the standard hour and minute hand, allowing you to see two time zones. But because this second time zone moves around the dial once every 24-hours instead of twice, it makes reading the 24-hour hand a little less intuitiveIts functionality is most helpful if you only need to check the time occasionally, like if you needed to call or communicate with someone in another time zone hence the nickname caller GMT.


A true GMT will have an independently setting hour hand that allows you to quickly adjust the hour forward or backward to match your current time zone. Because this is the hour hand you’re always reading, it makes it much easier to understand than trying to do the quick mental math required with a caller GMT. Hop on a flight from LA to New York and adjust the independent hour hand forward three hours viola; your 24-hour hand is still referencing LA time while your local time displays New York’s. The true GMT format is the more complicated of the two and is often preferred by frequent travelers. 


In a similar vein, there are also dual-time and world-timer complications which are also meant to help when traveling. A dual-time watch is just that, a watch that displays two time zones. A GMT is technically a dual-time watch, but not all dual-time watches are GMT’s. While there is a lot of overlap between the two, GMT’s always use a 24-hour hand while dual-time watches can use two 12-hour hands, two subdials, really any type of indicator of a second-time zone. The dual-time moniker is applied more broadly. 


A world-timer watch is more complicated than both the dual-time or GMT and displays the time in all the major time zones around the world simultaneously. All at a glance, one can quickly view their local time and the time in any major city across the globe, typically by using a rotating 24-hour disk representing the twenty-four time zones aligned with their corresponding cities. While GMT’s are often trendier travel watches, the world timer is the ultimate companion for any frequent flyer.


Jumping Hour

Most of the complications we’ve looked at so far are relatively common, but this next one—and the one after it—are rarely used and a bit quirky. The jumping hour hand takes what is usually a smooth transition and makes it abrupt in the name of accurate legibility. On a traditional mechanical watch, the hour hand will slowly move from one hour to the next as the minutes pass by within that hour. A jumping hour will not. The jumping hour hand remains in place on the hour until the 60th minute when it will jump suddenly to the next hour. This complication prevents one from accidentally reading, for example, 4:58 as 5:58 because the hour hand is so close to the five o’clock position at the end of the fourth hour. 


Dead Beat Seconds

Along a similar vein to the Jumping Hour, the dead beat second hand pauses every second rather than continuously moving. Mechanical watches are famous for their smoothly flowing seconds hands, but it can be hard to read the second precisely when the hand never stops. The dead beat second hand pauses briefly every second, allowing the wearer to easily read the time down to the second. Interestingly enthusiasts often use the second’s hand as a quick way to tell a mechanical watch from a quartz one as a quartz seconds hand also stops slightly every second. This is part of why the complication isn’t more common; those with mechanical watches don’t want their watches to be confused for quartz.

Grand Complications

Now for the crème de la crème, Grand Complications. A Grand Complication is the ultimate test of a watchmaker; it combines multiple high horology complications into one watch. While there is some debate on what exactly qualifies as a Grand Complication, the most common definition is a watch that contains a perpetual calendar, minute repeater, and a rattrapante or split-seconds chronograph all in one timepiece. However, most watches that are bestowed the title “Grand Complication” have many more than this. For example, the Vacheron Constantin Reference 57260—the most complicated (pocket)watch in the world—has 57 complications. 


What watch has the most complications?

The title of most complicated wristwatch in the world actually belongs to two wrist watches, the Vacheron Constantin Les Cabinotiers Celestia Astronomical Grand Complication 3600 has 23 complications and the  Franck Muller Aeternitas Mega 4 also has 23. To give you an idea of what that looks like in a watch, here is a list of all the complications in the Vacheron Les Cabinotiers.

On The Front:

  • Moonphase
  • Sunrise/sunset 
  • Length of day and night indicator
  • Zodiac sun sign indicator
  • Equinox and solstice indicators
  • Equation of time Marchant (which displays the difference between the actual length of the solar day, and the mean, or average, solar day, which is 24 hours.)
  • Perpetual calendar
  • Leap year indicator
  • Microscope which displays the relationship of the sun, moon, and ocean tides.

On The Back:

The thing about complications is that while they make a watchmaker’s life harder, their whole goal is to make your life easier. Complications can help you with all sorts of everyday tasks like timing a steak, knowing when to call home, or just what day it is. They offer a great amount of convenience and charm and make watches as a whole that much more interesting. Once you have this foundational understanding, you’ll find that watches actually aren’t that complicated.


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