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Watch Complications, Explained: An Expert Guide

Feature: Long Read
Words by Robin Swithinbank

Complication: the very word seems unnecessarily complicated. In plain English, a watchmaking complication is a function that goes beyond telling the time. Even a date counts as one. As you can imagine therefore, the range of complications produced by mechanical watchmakers is dizzying. Chronographs, tourbillons, GMTs, calendars – start here for your guide to the complications most often found in mechanical fine watches.


One of the most popular complications, a chronograph is a secondary timekeeping function that turns a wristwatch into a stopwatch for timing individual events, and can be easily identified by the ‘pushers’ that frame the case. Typically, chronographs will also be represented by a central seconds hand and an arrangement of sub-dials that show elapsed minutes and hours.

  • Flyback Chronograph

    With a function that allows users to reset and restart the stopwatch while it’s running with a single push of a button, flyback chronographs elevate the chronograph concept. They are particularly useful for keeping track of recurring events like recording lap times during a race.

  • Split-seconds Chronograph

    A split-seconds or double chronograph enables the user to track two events that start at the same time but finish independently of one another, such as two competitors in a race. It’s indicated by two central seconds hands, usually in different colours, that sit on top of one another when the chronograph is set running and then ‘split ’when the stop button is pressed for the first time.

  • Monopusher Chronograph

    Early chronographs used a single pusher to start, stop and reset the mechanism. That tradition lives on in monopusher chronographs, which often secrete that single pusher into a watch’s crown.

Tudor Black Bay GMT Stainless Steel and Yellow Gold Watch 41mm

Since the 1950s and the dawn of passenger air travel, watchmakers have been creating watches with GMT or second time zone functions that can display local and home time concurrently. Local time is shown by the central hour and minute hands, while a second display – often a single central hand pointing to a 24-hour scale – shows home time. This is sometimes known as a UTC (Universal Coordinated Time) function.

Pictured: Tudor

A. Lange & Söhne Rose Gold Lange 1 Time Zone Watch 41.9Mm

Invented in the 1930s by watchmaker Louis Cottier, a system for showing 24 of the world’s time zones on a watch simultaneously became one of the most fabled and collectable complications. Most commonly, this is represented by a ‘city ring’ that runs around the edge of a dial, indicating key world cities such as London, Tokyo, New York, and Sydney. By referencing these against a 24-hour scale, split into two colours to show day and night, you can read the time as it is anywhere in the world – without having to make the mental calculation.

Pictured: A. Lange & Söhne

Vacheron Constantin Rose Gold Patrimony Retrograde Day-Date Watch 42.5Mm

Most watches use circular scales, but not always. When a function such as the date or time is shown by a hand running along a linear scale, it’s known as a retrograde display. Once the hand has moved from one end of the scale to the other, it jumps back to the start and begins its path again.

Pictured: Vacheron Constantin


Whether the tourbillon – French for ‘whirlwind’ – is a complication at all is an eternal debate among horolophiles. Perfected in 1801 by one of the godfathers of mechanical watchmaking Abraham-Louis Breguet, it’s an anti-gravitational device originally designed for pocket watches, which regulates a timepiece’s accuracy by hosting its oscillating parts in a constantly revolving cage. It performs no function beyond that – and, given that wristwatches aren’t confined to one position in a pocket, it’s arguably redundant. However, the tourbillon remains a spectacular and compelling mechanical wonder, as well as a complex one to produce. So much so that only elite brands attempt to.

Flying Tourbillon

Experiments by some fine watch manufactures have led to new expressions of the tourbillon. Some watches even have multiple. One of the more familiar is the flying tourbillon, so named because it appears to float freely of the rest of the mechanism. It’s a neat trick, achieved by hiding the points at which it’s connected to the rest of the movement.

  • Full Calendar

    A full calendar watch is one that indicates the time, day, date, and month. Sometimes, it will show the phases of the moon, too. Full calendar watches must be manually adjusted for month lengths, either via the crown or a series of tiny pushers that are set into the case.

  • Annual Calendar

    A twist on the full calendar, an annual calendar watch indicates time, day, date, month, and phases of the moon – based on the Gregorian calendar – as well as keeping track of month lengths without the need for adjustment. The only exception is at the end of February, when it will need to be advanced manually.

  • Perpetual Calendar

    A perpetual calendar is one of the most desirable watchmaking complications. It indicates time, day, date, month, phase of the moon, leap year and sometimes the year as well, based on the Gregorian calendar. The perpetual calendar’s boast is that, if it’s kept wound, it won’t even need adjusting in leap years – at least, not until the end of this century.

Chopard L.U.C Perpetual Chrono Watch 45mm

One of the more poetic complications, a moonphase shows the waxing and waning of the moon over its 29.5-day lunar cycle. It’s typically displayed by a rotating disc that sits behind an opening on the dial.

Pictured: Chopard

Zenith Defy Diamond-Set El Primero 21 Automatic Watch 44mm
Power Reserve Indicator

Whether they’re automatic or hand-wound, all mechanical watches have a power reserve – the energy stored in a mainspring that’s coiled inside a chamber known as a ‘barrel’. By any other name, a mechanical battery. Power reserves start from around 40 hours and increase from there, with most lasting between two and three days. Some fine watches display this via a power reserve indicator, a clever feature on a hand-wound watch, where it can be especially useful to know when you’ll need to rewind.

Pictured: Zenith

  • Tachymeter

    Typically found alongside a chronograph, a tachymeter is a scale rather than a complication. It’s used to calculate speed over a known distance.

  • Telemeter

    Also a scale rather than a complication, a telemeter is used to calculate the distance between something you see first and hear second, such as the location of a storm – when you see lightning before hearing thunder.

Grand Complication

A grand complication isn’t a complication in its own right. The term is used to describe those watches that bring together several complications. How many is undefined – but, as an example, a watch with a chronograph and a perpetual calendar would qualify.

Pictured: IWC Schaffhausen

The Sounds

Not all complications are visible; the artform extends to audio, too.

  • Minute Repeater

    Invented before the dawn of electricity, minute repeaters were created for people of means who wanted to tell the time in the dark – chiming it on demand. They are activated via a slide in the side of the case, which sets off a system of hammers and gongs that mark the hours, quarters, and minutes in sequence.

  • Grande Sonnerie and Petite Sonnerie

    In simple terms, a grande sonnerie is a powered-up minute repeater that strikes the time on the hour and quarters in passing. Grande sonneries usually come with a silent mode so they can be turned off, since their tune could prove detrimental to sleep. A petite sonnerie chimes only the hours in passing.

  • Alarm

    Even though setting them is usually charmingly inaccurate, alarm watches still captivate. They tend to sound when the time reaches a point that’s set by a secondary central hand. This activates a chiming device – usually a hammer – that repeatedly strikes a gong inside the watch. Most alarm watches have a secondary power source exclusively for the alarm, which needs to be wound independently of the timekeeping function.

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