horology Chronometry or horology () is the science studying the measurement of time and timekeeping. Chronometry enables the establishment of standard measurements of time, which have applications in a broad range of social and scientific areas. ''Hor ...

, a complication is any feature of a

timepiece A clock or chronometer is a device that measures and displays time. The clock is one of the oldest Invention, human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, a ...

beyond the display of hours, minutes and seconds. A timepiece indicating only hours, minutes and seconds is known as a simple movement. Common complications include date or day-of-the-week indicators, alarms, chronographs (stopwatches), and automatic winding mechanisms. Complications may be found in any clock, but they are most notable in mechanical watches where the small size makes them difficult to design and assemble. A typical date-display chronograph may have up to 250 parts, while a particularly complex watch may have a thousand or more parts. Watches with several complications are referred to as ''grandes complications.''

Types

Timing

* Chronograph, with a second hand that can be stopped and started to function as a stopwatch. ** Double chronograph or ''rattrapante'', multiple second hands for split-second, lap timing or timing multiple events ** Flyback chronograph, allowing rapid reset of the chronograph as it is running ** Counter chronograph ** Independent second-hand chronograph ** Jumping second-hand chronograph *

Calendar date A calendar date is a reference to a particular day, represented within a calendar system, enabling a specific day to be unambiguously identified. Simple math can be performed between dates; commonly, the number of days between two dates may be ca ...

Day of the week In a vast number of languages, the names given to the seven days of the week are derived from the names of the classical planets in Hellenistic astronomy, which were in turn named after contemporary deities, a system introduced by the Sume ...

* 24-hour watch (with an hour hand sweeping through 24 divisions rather than twelve) * Display of

time zone A time zone is an area which observes a uniform standard time for legal, Commerce, commercial and social purposes. Time zones tend to follow the boundaries between Country, countries and their Administrative division, subdivisions instead of ...

s (usually, a second hour hand displays the

Coordinated Universal Time Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communicat ...

) * world time * Quickset date * small seconds - seconds are displayed in a subdial * ''Foudroyante'' (also called "flying seconds"- a dedicated hand that completes a full rotation in one second indicating fractions of a second) Many of these complications can result in watch defects, often due to watch owners manipulating mechanisms without an instruction manual, or disregarding "no-set-periods", time periods when no setting should be attempted, such as a certain phase before midnight when a watch with a date complication is already in the process of internally shifting discs.

Mechanical

* Self-winding, using the motion of the wrist and arm to recapture energy *

Power reserve indicator A power reserve indicator (originally called ) is a Complication (horology), complication of the watch, which is designed to show the amount of remaining stored energy. The power reserve indicator indicates the tension on the mainspring at any pa ...

or ''réserve de marche'' * Tourbillon, a mechanical refinement to an escapement that mitigates the effects of gravity on the operation of a timepiece * Retrograde indication (hands sweep through an arc of a circle instead of the full circle, usually 90°, they spring back to 0° when they reach the 90° point and start sweeping again) * Dead second (the second hand moves once per second instead of once per oscillation as in common mechanical movements)

Astronomical

* Annual calendar * Perpetual calendar *

Equation of time The equation of time describes the discrepancy between two kinds of solar time. The two times that differ are the apparent solar time, which directly tracks the diurnal motion of the Sun, and mean solar time, which tracks a theoretical mean Sun ...

and variations within the year * Time of

sunset Sunset (or sundown) is the disappearance of the Sun at the end of the Sun path, below the horizon of the Earth (or any other astronomical object in the Solar System) due to its Earth's rotation, rotation. As viewed from everywhere on Earth, it ...

and

sunrise Sunrise (or sunup) is the moment when the upper rim of the Sun appears on the horizon in the morning, at the start of the Sun path. The term can also refer to the entire process of the solar disk crossing the horizon. Terminology Although the S ...

Date of Easter As a moveable feast, the date of Easter is determined in each year through a calculation known as – often simply ''Computus'' – or as paschalion particularly in the Eastern Orthodox Church. Easter is celebrated on the first Sunday after the ...

* Sign of the

Zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north and south celestial latitude of the ecliptic – the apparent path of the Sun across the celestial sphere over the course of the year. Within this zodiac ...

* Moon phases * Mechanized

star chart A star chart is a celestial map of the night sky with astronomical objects laid out on a grid system. They are used to identify and locate constellations, stars, nebulae, galaxies, and planets. They have been used for human navigation since tim ...

Astrolabe An astrolabe (; ; ) is an astronomy, astronomical list of astronomical instruments, instrument dating to ancient times. It serves as a star chart and Model#Physical model, physical model of the visible celestial sphere, half-dome of the sky. It ...

dial * Planetarium dial * Display of zone

solar time Solar time is a calculation of the passage of time based on the position of the Sun in the sky. The fundamental unit of solar time is the day, based on the synodic rotation period. Traditionally, there are three types of time reckoning based ...

(as opposed to

standard time Standard time is the synchronization of clocks within a geographical region to a single time standard, rather than a local mean time standard. Generally, standard time agrees with the local mean time at some meridian that passes through the r ...

) * Display of true local

* Display of

sidereal time Sidereal time ("sidereal" pronounced ) is a system of timekeeping used especially by astronomers. Using sidereal time and the celestial coordinate system, it is easy to locate the positions of celestial objects in the night sky. Sidereal t ...

Striking

* Alarm * Passing strike (chiming watch) *

Repeater In telecommunications, a repeater is an electronic device that receives a signal and retransmits it. Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction. Some ...

Non-horological

By some definitions, a display on a watch may be a complication even if it is unrelated to time-telling. Some horologists discount non-horological features (even those tangential to timekeeping such as winding limitations mechanisms or power reserves) as being true complications. Examples include: *

Thermometer A thermometer is a device that measures temperature (the hotness or coldness of an object) or temperature gradient (the rates of change of temperature in space). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb ...

s *

Barometer A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis ...

s *

Compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with No ...

es *

Altimeter An altimeter or an altitude meter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth under water. Ty ...

Grand(e) complications

A ''grand(e) complication'' is a watch with several complications, the most complex achievements of ''haute horlogerie'', or fine watchmaking. Although there is no official definition, one common criterion is that a watch contain at least one (visible) timing complication, one astronomical complication, and one striking complication. Ultra-complicated watches are produced in strictly limited numbers, with some built as unique instruments. Some watchmaking companies known for making ultra-complicated watches are Breguet, Patek Philippe, and Vacheron Constantin. The initial ''ultra-complicated'' watches appeared due to watchmakers' ambitious attempts to unite a great number of functions in a case of a single timepiece. The mechanical clocks with a wide range of functions, including astronomical indications, suggested ideas to the developers of the first pocket watches. As a result, as early as in the 16th century, the horology world witnessed the appearance of numerous complicated and even ultra-complicated watches. As of November 2018, the top four most complicated mechanical watches ever created are manufactured by Vacheron Constantin and Patek Philippe, respectively. In particular, the Patek Philippe Henry Graves Supercomplication currently holds the title of the second most expensive watch ever sold at auction, with a final price of US$24 million (23,237,000 CHF wiss francs sold in

Geneva Geneva ( , ; ) ; ; . is the List of cities in Switzerland, second-most populous city in Switzerland and the most populous in French-speaking Romandy. Situated in the southwest of the country, where the Rhône exits Lake Geneva, it is the ca ...

on November 11, 2014. Two Patek Philippe Calibre 89 also currently rank among the top 10 most expensive watches ever sold at auction, with final prices over 5 million US dollars. # The Vacheron Constantin Les Cabinotiers Solaria Ultra Grand Complication – La Première, unveiled in 2025, is now widely regarded as the most complicated wristwatch in the world, featuring 41 complications and 1,521 components. Developed over eight years by a single watchmaker, it includes astronomical functions, a perpetual calendar, tide indicators, a minute repeater, and more. Powered by the Calibre 3655 with 13 patents, it was launched for the brand’s 270th anniversary at Watches and Wonders 2025. # The Patek Philippe Calibre 89 has 33 complications, using a total of 1728 parts. It was released in 1989 to commemorate the 150th anniversary of the company. The complications include the date of

Easter Easter, also called Pascha ( Aramaic: פַּסְחָא , ''paskha''; Greek: πάσχα, ''páskha'') or Resurrection Sunday, is a Christian festival and cultural holiday commemorating the resurrection of Jesus from the dead, described in t ...

, and a 2800-star celestial chart. # The Supercomplication delivered to Henry Graves, Jr. in 1933 has 24 complications. The watch was reportedly the culmination of a watch arms race between Graves and James Ward Packard. The Super-complication took three years to design and five to build, and sports a chart of the nighttime sky at Graves' home in New York. It remains the most complicated watch (920 parts) built without the assistance of computers. # The Star Caliber 2000 has 21 complications. They include sunrise and sunset times and the lunar orbit, and it is capable of playing the melody of Westminster quarters (from Big Ben, the clock tower of the

Houses of Parliament The Palace of Westminster is the meeting place of the Parliament of the United Kingdom and is located in London, England. It is commonly called the Houses of Parliament after the House of Commons and the House of Lords, the two legislative ch ...

in London). The

Franck Muller Franck Muller is a Switzerland, Swiss luxury watch manufacturer named after its founder. The company's estimated total sales (in 2010/2011) were 20000 pkr in watches with an average unit price of 679000 pkr Franck Muller's watches are worn by va ...

Aeternitas Mega 4 is the world's most complicated wristwatch. It has 36 complications, 25 of them visible, 1483 components and 1000-year calendar. Blancpain is famous for being the creator of one of the most complicated

mechanical watch A mechanical watch is a watch that uses a Movement (clockwork), clockwork mechanism to measure the passage of time, as opposed to quartz watches which function using the vibration modes of a piezoelectric quartz tuning fork, or radio clock, radio ...

es ever made, the Blancpain 1735, which is a true grand complication ( Tourbillon, minute repeater, perpetual calendar, split chrono), a limited edition of 30 pieces only, production of just one piece per year. The Hybris Mechanica Grande Sonnerie is the world's second most complicated wristwatch. Powered by the Jaeger LeCoultre Calibre 182 movement, with 27 complications and over 1300 parts. The movement is housed in a 44mm by 15mm 18k white gold case.

Use in smartwatches

smartwatch A smartwatch is a portable wearable computer that resembles a wristwatch. Most modern smartwatches are operated via a touchscreen, and rely on mobile apps that run on a connected device (such as a smartphone) in order to provide core functions. ...

es, complications are features other than time display, implemented in software.a. "Complications", Apple Developer Human Interface Guidelines

br />b. "Creating Complications for Your watchOS App

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References

External links

* {{timezones Timekeeping components Watches