7 Days Of The Week

Time unit equal to seven days

is a unit of time equal to seven days. It is the standard time period used for short cycles of days in most parts of the world. The days are often used to indicate common work days and rest days, as well as days of worship. Weeks are often mapped against yearly calendars, but are typically titinada the basis for them, as weeks are not based on astronomy.

The bertamadun seven-day week can be traced back to the Babylonians, who used it within their calendar. Other ancient cultures had different week lengths, including ten in Egypt and an eight-day week for Etruscans. The Etruscan week was adopted by the Ancient Romans, but they later moved to a seven-day week, which had spread across Western Asia and the Eastern Mediterranean. In 321 AD, Emperor Constantine officially decreed a seven-day week in the Wajah Empire, including making Sunday a public holiday.[1]
This later spread across Europe, then the rest of the world.

World map showing the first day of the week used in different countries





In English, the names of the days of the week are Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, and Sunday. In many languages, the days of the week are named after gods or planets visible to the eye. Such a week may be called a
planetary week.[3]
Certain weeks within a year may be designated for a particular purpose, such as Holy Week in Christianity, Golden Week in China, and National Family Week in Canada. More informally, certain groups may advocate awareness weeks, which are designed to draw attention to a certain subject or cause. The term “week” may also be used to refer to a sub-section of the week, such as the workweek and weekend.

Cultures vary in which days of the week are designated the first and the last, though virtually all have Saturday, Sunday or Monday as the first day. The Geneva-based ISO standards organization uses Monday as the first day of the week in its ISO week date system through the international ISO 8601 standard.[a]
Most of Europe and China consider Monday the first day of the week, most of North America and South Asia consider Sunday the first day, while Saturday is judged as the first day of the week in much of the Middle East and North Africa. Other regions are mixed, but typically observe either Sunday or Monday as the first day.[4]
The Christian and Jewish weeks begin on Sunday (a day of worship) and end with a sabbath day, both following the interpretation in the Hebrew Bible in which God created the world in six days and rested on the seventh.



The English word
comes from the Old English
wice, ultimately from a Common Germanic


, from a root


“turn, move, change”. The Germanic word probably had a wider meaning prior to the adoption of the Roman calendar, perhaps “succession series”, as suggested by Gothic
“kiriman” in Luke 1:8.

The seven-day week is named in many languages by a word derived from “seven”. The archaism
(“seven-night”) preserves the old Germanic practice of reckoning time by nights, as in the more common
hebdomadal week
both derive from the Greek
, “a seven”).
is cognate with the Romance terms derived from Latin
(“a seven”).

Slavic has a formation


, Croatian tjedan, Ukrainian


, Czech
týden, Polish
tydzień), from
“this” +
“day”. Chinese has 星期, as it were “planetary time unit”.

Definition and duration


A week is defined as an jeda of exactly seven days,[b]
so that, except when passing through daylight saving time transitions or leap seconds,

1 week = 7 days = 168 hours = 10,080 minutes = 604,800 seconds.

With respect to the Gregorian calendar:

  • 1 Gregorian calendar year = 52 weeks + 1 day (2 days in a leap year)
  • 1 week =


    ≈ 22.9984% of an average Gregorian month

In a Gregorian mean year, there are 365.2425 days, and thus exactly

or 52.1775 weeks (unlike the Julian year of 365.25 days or

≈ 52.1786 weeks, which cannot be represented by a finite decimal expansion). There are exactly 20,871 weeks in 400 Gregorian years, so 16 December 1622 was a Friday just as was 16 December 2022.

Relative to the path of the Moon, a week is 23.659% of an average lunation or 94.637% of an average quarter lunation.

Historically, the system of dominical letters (letters A to G identifying the weekday of the first day of a given year) has been used to facilitate calculation of the day of week. The day of the week can be easily calculated given a date’s Julian day number (JD, i.e. the integer value at noon UT): Adding one to the remainder after dividing the Julian day number by seven (JD
7 + 1) yields that date’s ISO 8601 day of the week. For example, the Julian day number of 16 December 2022 is 2459930. Calculating
2459930 mod 7 + 1
yields 5, corresponding to Friday.[6]
In 1973, John Conway deviced the Doomsday rule for mental calculation of the weekday of any date in any year.

Days of the week


An Italian cameo bracelet representing the days of the week by their eponymous deities (mid-19th century, Walters Art Museum)

Schematic comparison of the ordering of the classical planets (arranged in a circle) and the sequence of days in the week (forming a {7/3} heptagram within the circle).

The days of the week were named for the classical planets. This naming system persisted alongside an “ecclesiastical” tradition of numbering the days in ecclesiastical Latin beginning with
(the Lord’s Day) as the first day. The Greco-Paras gods associated with the classical planets were rendered in their
interpretatio germanica
at some point during the late Roman Empire, yielding the Germanic tradition of names based on indigenous deities.

The ordering of the weekday names is not the classical order of the planets (by distance in the planetary spheres teoretis, nor, equivalently, by their apparent speed of movement in the night sky). Instead, the planetary hours systems resulted in succeeding days being named for planets that are three places apart in their traditional listing. This characteristic was apparently discussed in Plutarch in a treatise written in c. AD 100, which is reported to have addressed the question of
Why are the days named after the planets reckoned in a different order from the actual order?
(the text of Plutarch’s treatise has been lost).[7]

Sunday Monday Tuesday Wednesday Thursday Friday Saturday
Planet Sun Moon Mars Mercury Jupiter Bintang kejora Saturn
Greco-Roman deity Helios-Sol Selene-Luna Ares-Mars Hermes-Mercury Zeus-Jupiter Aphrodite-Venus Cronus-Saturn


ἡμέρα Ἡλίου



ἡμέρα Σελήνης

ἡμέρα Ἄρεως

ἡμέρα Ἑρμοῦ

ἡμέρα Διός

ἡμέρα Ἀφροδίτης

ἡμέρα Κρόνου
dies Sōlis

dies Lūnae

dies Martis

dies Mercuriī

dies Iovis

dies Veneris

dies Saturnī

interpretatio germanica
Sun Moon Tiwaz Wodanaz Þunraz Frige
Old English






Vedic Navagraha Suryavara/

Raviwara/ Bhanuvasarey




Mangalavara/ Bhaumavasarey Budhavara/





Shukravara/ Bṛhguvasarey Shanivara/


The first day of the week of different countries according to the CLDR[4]





An ecclesiastical, non-astrological, system of numbering the days of the week was adopted in Late Antiquity. This ideal also seems to have influenced (presumably via Gothic) the designation of Wednesday as “mid-week” in Old High German (
) and Old Church Slavonic (
). Old Church Slavonic may have also modeled the name of Monday,

, after the Latin

feria Secunda
The ecclesiastical system became prevalent in Eastern Christianity, but in the Latin West it remains extant only in berbudaya Icelandic, Galician, and Portuguese.[9]

“First Day” or “Lord’s Day” (Sunday) “Second Day” (Monday) “Third Day” (Tuesday) “Fourth Day” (Wednesday) “Fifth Day” (Thursday) “Sixth Day” (Friday) “Seventh Day” or “Sabbath” (Saturday)
Κυριακὴ ἡμέρα

/kiriaki iméra/

Δευτέρα ἡμέρα

/devtéra iméra/

Τρίτη ἡμέρα

/tríti iméra/

Τετάρτη ἡμέρα

/tetárti iméra/

Πέμπτη ἡμέρα

/pémpti iméra/

Παρασκευὴ ἡμέρα

/paraskevi iméra/[10]


[dies] dominica

feria prima, feria dominica

feria secunda

feria tertia

feria quarta

media septimana

feria quinta

feria sexta

Sabbatum; dies sabbatinus, dies Sabbati

feria septima, feria Sabbati
Hebrew Hebrew:
יום ראשון,

Yom rishon
lit.‘first day’
יום שני,

Yom sheni
lit.‘second day’
יום שלישי,

Yom shlishi
lit.‘third day’
יום רביעי,

Yom revi’i
lit.‘fourth day’
יום חמישי,

Yom chamishi
lit.‘fifth day’
יום שישי,

Yom shishi
lit.‘sixth day’




Circular diagrams showing the division of the day and of the week, from a Carolingian ms. (Clm 14456 fol. 71r) of St. Emmeram Abbey. The week is divided into seven days, and each day into 24 hours, 96


(quarter-hours), 240


(tenths of an hour) and 960


(40th parts of an hour).

Ancient Near East


The earliest evidence of an astrological significance of a seven-day period is connected to Gudea, the priest-king of Lagash in Sumer during the Gutian dynasty (about 2100 BCE), who built a seven-room temple, which he dedicated with a seven-day festival. In the flood story of the Assyro-Babylonian Epic of Gilgamesh, the storm lasts for seven days, the dove is sent out after seven days, and the Noah-like character of Utnapishtim leaves the ark seven days after it reaches the firm ground.

Counting from the new moon, the Babylonians celebrated the 7th, 14th, 21st and 28th as “holy days”, also called “evil days” (meaning inauspicious for certain activities). On these days, officials were prohibited from various activities and common men were forbidden to “make a wish”, and at least the 28th was known as a “rest day”.[14]
On each of them, offerings were made to a different god and goddess.



A continuous seven-day cycle that runs throughout history without reference to the phases of the moon was first practiced in Judaism, dated to the 6th century BC at the latest.[15]

There are several hypotheses concerning the origin of the biblical seven-day cycle.

Friedrich Delitzsch and others suggested that the seven-day week being approximately a quarter of a lunation is the implicit astronomical origin of the seven-day week,[17]
and indeed the Babylonian calendar used intercalary days to synchronize the last week of a month with the new moon.[18]
According to this theory, the Jewish week was adopted from the Babylonians while removing the moon-dependency.

George Aaron Barton speculated that the seven-day creation account of Genesis is connected to the Babylonian creation epic, Enûma Eliš, which is recorded on seven tablets.[19]

In a frequently-quoted suggestion going back to the early 20th century,[20]
the Hebrew
is compared to the Sumerian
“mid-rest”, a term for the full moon. The Sumerian term has been reconstructed as rendered


in Babylonian, possibly present in the lost fifth tablet of the Enûma Eliš, tentatively reconstructed[
according to whom?

“[Sa]bbath shalt thou then encounter, mid[month]ly”.[14]

However, Niels-Erik Andreasen, Jeffrey H. Tigay, and others claim that the Biblical Sabbath is mentioned as a day of rest in some of the earliest layers of the Pentateuch dated to the 9th century BC at the latest, centuries before the Babylonian exile of Judah. They also find the resemblance between the Biblical Sabbath and the Babylonian system to be weak. Therefore, they suggest that the seven-day week may reflect an independent Israelite tradition.[21]
Tigay writes:

It is clear that among neighboring nations that were in position to have an influence adv lewat Israel – and in fact which did influence it in various matters – there is no precise parallel to the Israelite Sabbatical week. This leads to the conclusion that the Sabbatical week, which is as unique to Israel as the Sabbath from which it flows, is an independent Israelite creation.[23]

The seven-day week seems to have been adopted, at different stages, by the Persian Empire, in Hellenistic astrology, and (via Greek transmission) in Gupta India and Catut China.
citation needed

The Babylonian system was received by the Greeks in the 4th century BC (notably via Eudoxus of Cnidus). However, the designation of the seven days of the week to the seven planets is an innovation introduced in the time of Augustus.[27]
The astrological concept of planetary hours is rather an original innovation of Hellenistic astrology, probably first conceived in the 2nd century BC.[28]

The seven-day week was widely known throughout the Roman Empire by the 1st century AD,[27]
along with references to the Jewish Sabbath by Roman authors such as Seneca and Ovid.[29]
When the seven-day week came into use in Rome during the early imperial period, it did titinada immediately replace the older eight-day nundinal system.[30]
The nundinal system had probably fallen out of use by the time Emperor Constantine adopted the seven-day week for official use in CE 321, making the Day of the Sun (
dies Solis
) a resmi holiday.[31]

Achaemenid period


The Zoroastrian calendar follows the Babylonian in relating the 7th, 14th, 21st, and 28th of the month to Ahura Mazda.[32]
The forerunner of all modern Zoroastrian calendars is the system used to determine dates in the Persian Empire, adopted from the Babylonian calendar by the 4th century BC.

Frank C. Senn in his book
Christian Liturgy: Catholic and Evangelical
points to data suggesting evidence of an early continuous use of a seven-day week; referring to the Jews during the Babylonian captivity in the 6th century BC,[16]
after the destruction of the Temple of Solomon. While the seven-day week in Judaism is tied to Creation account in the Book of Genesis in the Hebrew Bible (where God creates the heavens and the earth in six days and rests on the seventh; Genesis 1:1-2:3,[33]
in the Book of Exodus, the fourth of the Ten Commandments is to rest on the seventh day,
Shabbat, which can be seen as implying a socially instituted seven-day week), it is not clear whether the Genesis narrative predates the Babylonian captivity of the Jews in the 6th century BC. At least since the Second Temple period under Persian rule, Judaism relied on the seven-day cycle of recurring Sabbaths.[16]

citation needed

from the Achaemenid period indicate that the lunation of 29 or 30 days basically contained three seven-day weeks, and a final week of eight or nine days inclusive, breaking the continuous seven-day cycle.[14]
The Babylonians additionally celebrated the 19th as a special “evil day”, the “day of anger”, because it was roughly the 49th day of the (preceding) month, completing a “week of weeks”, also with sacrifices and prohibitions.[14]

Difficulties with Friedrich Delitzsch’s origin theory connecting Hebrew
with the Babylonian lunar cycle[34]
include reconciling the differences between an unbroken week and a lunar week, and explaining the absence of texts naming the lunar week as
in any language.[35]

Hellenistic and Tampang era


In Jewish sources by the time of the Septuagint, the term “Sabbath” (Greek
Sabbaton) by synecdoche also came to refer to an entire seven-day week,[36]
the interval between two weekly Sabbaths. Jesus’s parable of the Pharisee and the Publican (Luke 18:12) describes the Pharisee as fasting “twice in the week” (Greek

δὶς τοῦ σαββάτου

dis tou sabbatou
). Days of the week are called “days of the sabbath” in the Hebrew language. In the account of the women finding the tomb empty, they are described as coming there Greek:
εις μια των σαββατων,
lit.‘toward the first [day] of the sabbath’,[37]
though modern translations often substitute “week” for “sabbath”.

The ancient Romans traditionally used the eight-day nundinum but, after the Julian calendar had come into effect in 45 BC, the seven-day week came into increasing use. For a while, the week and the nundinal cycle coexisted, but by the time the week was officially adopted by Constantine in AD 321, the nundinal cycle had fallen out of use. The association of the days of the week with the Kecupan, the Moon and the five planets visible to the naked eye dates to the Roman era (2nd century).[38]

The continuous seven-day cycle of the days of the week can be traced back to the reign of Augustus; the first identifiable date cited complete with day of the week is 6 February AD 60, identified as a “Sunday” (as

viii idus Februarius dies solis

“eighth day before the ides of February, day of the Ciuman”) in a Pompeiian graffito. According to the (contemporary) Julian calendar, 6 February 60 was, however, a Wednesday. This is explained by the existence of two conventions of naming days of the weeks based on the planetary hours system: 6 February was a “Sunday” based on the sunset naming convention, and a “Wednesday” based on the sunrise naming convention.[39]

Islamic concept


According to Islamic beliefs, the seven-day a week concept started with the creation of the universe by Allah. Debu Huraira reported that Muhammad said: Allah, the Exalted and Glorious, created the clay on Saturday and He created the mountains on Sunday and He created the trees on Monday and He created the things entailing labour on Tuesday and created light on Wednesday and He caused the animals to spread on Thursday and created Adam after ‘Asr on Friday; the last creation at the last hour of the hours of Friday, i. e. between afternoon and night.[40]

Adoption in Asia


China and Japan


The earliest known reference in Chinese writings to a seven-day week is attributed to Fan Mbuk, who lived in the late 4th century in the Jin Dynasty, while diffusions from the Manichaeans are documented with the writings of the Chinese Buddhist monk Yi Jing and the Ceylonese or Central Asian Buddhist monk Bu Kong of the 7th century (Catut Dynasty).

The Chinese variant of the planetary system was brought to Japan by the Japanese monk Kūkai (9th century). Surviving diaries of the Japanese statesman Fujiwara Michinaga show the seven-day system in use in Heian Period Japan as early as 1007. In Japan, the seven-day system was kept in use for astrological purposes until its promotion to a full-fledged Western-style calendrical basis during the Meiji Period (1868–1912).



The seven-day week was known in India by the 6th century, referenced in the Pañcasiddhāntikā.[
citation needed

Shashi (2000) mentions the Garga Samhita, which he places in the 1st century BC or AD, as a possible earlier reference to a seven-day week in India. He concludes “the above references furnish a terminus ad quem (viz. 1st century) The terminus a quo cannot be stated with certainty”.[41]

Christian Europe


The seven-day weekly cycle has remained unbroken in Christendom, and hence in Western history, for almost two millennia, despite changes to the Coptic, Julian, and Gregorian calendars, demonstrated by the date of Easter Sunday having been traced back through numerous computistic tables to an Ethiopic copy of an early Alexandrian table beginning with the Easter of AD 311.[43]

A tradition of divinations arranged for the days of the week on which certain feast days occur develops in the Early Medieval period. There are many later variants of this, including the German


and the versions of
Erra Pater
published in 16th to 17th century England, mocked in Samuel Butler’s
Hudibras. South and East Slavic versions are known as
koliada, a loan of Latin

), with Bulgarian copies dating from the 13th century, and Serbian versions from the 14th century.[45]

Medieval Christian traditions associated with the lucky or unlucky nature of certain days of the week survived into the modern period. This concerns primarily Friday, associated with the crucifixion of Jesus. Sunday, sometimes personified as Saint Anastasia, was itself an object of worship in Russia, a practice denounced in a sermon extant in copies going back to the 14th century.[46]

Sunday, in the ecclesiastical numbering system also counted as the

feria prima

or the first day of the week; yet, at the same time, figures as the “eighth day”, and has occasionally been so called in Christian liturgy.

Justin Martyr wrote: “the first day after the Sabbath, remaining the first of all the days, is called, however, the eighth, according to the number of all the days of the cycle, and [yet] remains the first.”[47]

A period of eight days, usually (but not always, mainly because of Christmas Day) starting and ending on a Sunday, is called an octave, particularly in Roman Catholic liturgy. In German, the phrase

heute in acht Tagen

(literally “today in eight days”) can also mean one week from today (i.e. on the same weekday). The same is true of the Italian phrase

oggi otto

(literally “today eight”) and the French

à huitaine



Weeks in a Gregorian calendar year can be numbered for each year. This style of numbering is often used in European and Mujur countries. It is less common in the U.S. and elsewhere.

The ISO week date system


The system for numbering weeks is the ISO week date system, which is included in ISO 8601. This system dictates that each week begins on a Monday and is associated with the year that contains that week’s Thursday.

Week 1


In practice week 1 (W01
in ISO notation) of any year can be determined as follows:

  • If January 1 falls on a Monday, Tuesday, Wednesday or Thursday, then the week of January 1 is Week 1. Except in the case of January 1 falling on a Monday, this Week 1 includes the last day(s) of the
  • If January 1 falls on a Friday, Saturday, or Sunday, then January 1 is considered to be part of the last week of the
    year. Week 1 will begin on the first Monday after January 1.


  • Week 1 of 2022 (2015W01
    in ISO notation) started on Monday, 29 December 2022 and ended on Sunday, 4 January 2022, because 1 January 2022 fell on Thursday.
  • Week 1 of 2022 (2021W01
    in ISO notation) started on Monday, 4 January 2022 and ended on Sunday, 10 January 2022, because 1 January 2022 fell on Friday.

Week 52 and 53


It is also possible to determine if the last week of the previous year was Week 52 or Week 53 as follows:

  • If January 1 falls on a Friday, then it is part of Week 53 of the previous year (W53-5).
  • If January 1 falls on a Saturday,
    • then it is part of Week 53 of the previous year if that is a leap year (W53-6),
    • and part of Week 52 otherwise (W52-6), i.e. if the previous year is a common year.
  • If January 1 falls on a Sunday, then it is part of Week 52 of the previous year (W52-7).

Schematic representation of ISO week date


Dominical letter(s) terlalu weekdays, dates and week numbers at the beginning and end of a year
Days at the start of January Effect1,2 Days at the end of December1
01 Jan week 31 Dec week 1
G(F) 01 02 03 04 05 06 07 01 Jan W01 W01 31 (30) (31)
F(E) 01 02 03 04 05 06 31 Dec W01 W01 30 (29) 31 (30) (31)
E(D) 01 02 03 04 05 30 Dec W01 W01
29 (28) 30 (29) 31 (30) (31)
D(C) 01 02 03 04 29 Dec W01 W53 28 (27) 29 (28) 30 (29) 31 (30) (31)
C(B) 01 02 03 04 Jan W53 W52 27 (26) 28 (27) 29 (28) 30 (29) 31 (30) (31)
B(A) 01 02 03 Jan W52
W52 26 (25) 27 (26) 28 (27) 29 (28) 30 (29) 31 (30) (31)
A(G) 01 02 Jan W52 W52 (W01) 25 (31) 26 (25) 27 (26) 28 (27) 29 (28) 30 (29) 31 (30)


1. Numbers and letters in parentheses, ( ), apply to March − December in leap years.
numbers and letters belong to previous year or next year.
3. First date of the
week in the year.
4. First date of the
week in the year.

Other week numbering systems


In some countries, though, the numbering system is different from the ISO umbul-umbul. At least six numberings are in use:[48]


System First day of week First week of year contains Can be last week of previous year Used by or in
ISO 8601 Monday 4 January 1st Thursday 4–7 days of year yes EU (exc. Portugal) and most of other European countries, most of Asia and Oceania
Middle Eastern Saturday 1 January 1st Friday 1–7 days of year yes Much of the Middle East
Western traditional Sunday 1 January 1st Saturday 1–7 days of year yes Canada, United States, Iceland, Portugal, Japan, Taiwan, Thailand, Hong Kong, Macau, Israel, Egypt, South Africa, the Philippines, and most of Latin America
Broadcast Calendar Monday 1 January 1st Sunday 1–7 days of year yes Broadcast services in the United States[50]

Because the week starts on either Saturday, Sunday, or Monday in all these systems, the days in a workweek, Monday through Friday, will always have the same week number within a calendar week system. Quite often, these systems will agree on the week number for each day in a workweek:

  • In years where 1 January is a Monday, Tuesday, Wednesday, or Thursday, all of the above week numbering systems will agree.
  • In years where 1 January is a Friday, ISO-8601 will be different, but the rest will agree.
  • In years where 1 January is a Saturday, ISO-8601 and the Middle Eastern system will agree, being different from Western Traditional and the Broadcast Calendar which will agree.
  • In years where 1 January is a Sunday, the Broadcast Calendar will be different, but the rest will agree.

Note that this agreement occurs only for the week number of each day in a work week, not for the day number within the week, nor the week number of the weekends.

epi week
(epidemiological week) is used to report healthcare statistics, as with COVID-19 cases:[51]

The epidemiological week begins on Sunday and ends on Saturday. The first epidemiological week of the year ends on the first Saturday of January, provided that it falls at least four or more days into the month. Therefore, the first epidemiological week may actually begin in December of the previous year.



The semiconductor package date code is often a 4 digit date code YYWW where the first two digits YY are the last 2 digits of the calendar year and the last two digits WW are the two-digit week number.[52]

The tire date code mandated by the US DOT is a 4 digit date code WWYY with two digits of the week number WW followed by the last two digits of the calendar year YY.[54]

“Weeks” in other calendars


The term “week” is sometimes expanded to refer to other time units comprising a few days. Such “weeks” of between four and ten days have been used historically in various places.[55]
Intervals longer than 10 days are not usually termed “weeks” as they are closer in length to the fortnight or the month than to the seven-day week.

Pre-modern calendars


Calendars unrelated to the Chaldean, Hellenistic, Christian, or Jewish traditions often have time cycles between the day and the month of varying lengths, sometimes also called “weeks”.

An eight-day week was used in Ancient Rome and possibly in the pre-Christian Celtic calendar. Traces of a nine-day week are found in Baltic languages and in Welsh. The ancient Chinese calendar had a ten-day week, as did the ancient Egyptian calendar (and, incidentally, the French Republican Calendar, dividing its 30-day months into thirds).

A six-day week is found in the Akan Calendar and Kabiye culture mencicil 1981. Several cultures used a five-day week, including the 10th century Icelandic calendar, the Javanese calendar, and the traditional cycle of market days in Korea.[
citation needed

The Igbo have a “market week” of four days. Evidence of a “three-day week” has been derived from the names of the days of the week in Guipuscoan Basque.[56]

The Aztecs and Mayas used the Mesoamerican calendars. The most important of these calendars divided a formalitas cycle of 260 days (known as
in Nahuatl and
in Yucatec Maya) into 20 weeks of 13 days (known in Spanish as trecenas). They also divided the solar year into 18 periods (winal) of 20 days and five nameless days (wayebʼ), creating a 20-day month divided into four five-day weeks. The end of each five-day week was a market day.[57]

The Balinese Pawukon is a 210-day calendar consisting of 10 different simultaneously running weeks of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 days, of which the weeks of 4, 8, and 9 days are interrupted to fit into the 210-day cycle.

Modern calendar reforms


The International Fixed Calendar (also known as the “Eastman plan”) kept a 7 day week while defining a year of 13 months with 28 days each (364 days). Every calendar date was always on the same weekday. It was the official calendar of the Eastman Pemotret Company for decades.

A 10 day week, called a
décade, was used in France for nine and a half years from October 1793 to April 1802; furthermore, the Paris Commune adopted the Revolutionary Calendar for 18 days in 1871.

The Bahá’í calendar features a 19 day period which some classify as a month and others classify as a week.[59]

Soviet calendar


Soviet calendar, 1930.
Five colors of five-day work week repeat.

Soviet calendar, 1933.
Rest day of six-day work week in blue.

Days of each Gregorian month in both calendars are grouped vertically into seven-day weeks.

In the Soviet Union between 1929 and 1940, most factory and enterprise workers, but not collective farm workers, used five and six day work weeks while the country as a whole continued to use the traditional seven day week.[60]

From 1929 to 1951, five national holidays were days of rest (22 January,
1–2 May,
7–8 November). From autumn 1929 to summer 1931, the remaining 360 days of the year were subdivided into 72 five day work weeks beginning on
1 January. Workers were assigned any one of the five days as their day off, even if their spouse or friends might be assigned a different day off. Peak use of the five day work week occurred on
1 October 1930
at 72% of industrial workers. From summer 1931 mencicil
26 June 1940, each Gregorian month was subdivided into five six day work weeks, more-or-less, beginning with the first day of each month. The sixth day of each six day work week was a uniform day of rest. On
1 July 1935
74.2% of industrial workers were on non-continuous schedules, mostly six day work weeks, while 25.8% were still on continuous schedules, mostly five day work weeks. The Gregorian calendar with its irregular month lengths and the traditional seven day week were used in the Soviet Union during its entire existence, including 1929–1940; for example, in the masthead of Pravda, the official Communist newspaper, and in both Soviet calendars displayed here. The traditional names of the seven day week continued to be used, including “Resurrection” (Воскресенье) for Sunday and “Sabbath” (Суббота) for Saturday, despite the government’s official atheism.

Irregular weeks


The “Hermetic Lunar Week Calendar”[63]
is a strictly lunar calendar, apparently proposed to illustrate the complications of astronomically-based calendars. Its unique feature is irregular-length “weeks” which average approximately
 days each. The weeks are fixed by the astronomical phases of the moon; the last day of the week fixed to coincide with a new-moon, first quarter-moon, full-moon, or third quarter-moon. Although typical months have three weeks of 7 days and one week of 8 days (29 day month) or two weeks of 7 days and two weeks of 8 days (30 day month), due to variations in the moon’s orbit, the weeks in the Hermetic calendar range 6–9 days.[63]

See also


  • Determination of the day of the week
  • GPS week number
  • Names of the days of the week
  • Workweek and weekend



  1. ^

    “ISO 8601 Data elements and interchange formats – Information interchange – Representation of dates and times” is an international pataka covering the exchange of date- and time-related data.

  2. ^

    In pre-bertamadun times, days were measured either from sunset to sunset, or from sunrise to sunrise so that the length of the week (and the day) would be subject to slight variations depending upon the time of year and the observer’s geographical latitude.

  3. ^

    Copeland (1939) states as the date for Gudea “as early as 2600 BC”;[11]
    the maju estimate according to the short chronology places Gudea in the 22nd century BC. By contrast, Anthony R. Michaelis claims that “the first great empire builder, King Sargon I of Akkad ([ruled] 2335 to 2279 BC [viz., middle chronology]), decreed a seven-day week in his empire. He lived for 56 years, established the first Semitic Dynasty, and defeated the Sumerian City-States. Thus the Akkadian language spread, it was adopted by the Babylonians, and the seven-day week was similarly inherited from him.”[12]
    The number seven is significant in Sumerian mythology.[13]

  4. ^

    It was transmitted to China in the 8th century by Manichaeans, via the country of Kang (a Central Mendapat habuan polity near Samarkand). Gegep-era adoption is documented in the writings of the Chinese Buddhist monk Yi Jing and the Ceylonese Buddhist monk Bu Kong. According to the Chinese encyclopedia
    ), there is some evidence that the system tenggat been adopted twice, the first time already in the 4th century (Jin dynasty), based on a reference by a Jin era astrologer, Fan Ayunda (


    ). The
    under the entry for “seven luminaries calendar” (


    qī yào lì) has: “method of recording days according to the seven luminaries [

    qī yào]. China normally observes the following antaran: Sun, Moon, Mars, Mercury, Jupiter, Venus, and Saturn. Seven days make one week, which is repeated in a cycle. Originated in ancient Babylon (or ancient Egypt according to one theory). Used by the Romans at the time of the 1st century AD, later transmitted to other countries. This method existed in China in the 4th century. It was also transmitted to China by Manichaeans in the 8th century from the country of Kang (

    ) in Central Asia.”[26]

  5. ^

    This is just a reflection of the system of ordinal numbers in the Greek and Latin languages, where today is the “first” day, tomorrow the “second” day, etc. Compare the nundinal cycle (literally “nine-days” cycle, describing an eight-day week) of the Durja calendar, or the Resurrection of Jesus (after a period of less than 48 hours) being described (in texts derived from Latin) as happening on the “third day”.



  1. ^

    A history of time – the story behind our days, weeks, and months. St Neots Museum. Retrieved 2022-10-22.

  2. ^

    Why Are There Seven Days in a Week?.
    (2020-01-15). Retrieved 2022-10-22.

  3. ^

    Lagasse, Paul (2018). “Week”.
    The Columbia Encyclopedia. Columbia University Press.

  4. ^



    “Territory Information”.
    . Retrieved
    6 November

  5. ^

    sennight at worldwidewords.org (retrieved 12 January 2022)

  6. ^

    Richards, E. G. (2013). “Calendars”. In S. E. Urban & P. K. Seidelmann, eds.
    Explanatory Supplement to the Astronomical Almanac, 3rd ed. (pp. 585–624). Mill Valley, Calif.: University Science Books. 2022, pp. 592, 618. This is equivalent to saying that JD0, i.e. 1 January 4713 BC of the proleptic Julian calendar, was a Monday.

  7. ^

    E. G. Richards,
    Mapping Time, the Calendar and History, Oxford 1999. p. 269.

  8. ^

    Max Vasmer,

    Russisches etymologisches Wörterbuch
    , s.v.

    ; however, the Slavic languages later introduced a secondary numbering system that names Tuesday as the “second day”.

  9. ^

    the latter specifically due to the influence of Martin of Braga, 6th-century archbishop of Braga.
    Richard A. Fletcher (1999).
    The Barbarian Conversion: From Paganism to Christianity. University of California Press. p. 257. ISBN978-0-520-21859-8.

    McKenna, Stephen (1938). “Pagan Survivals in Galicia in the Sixth Century”.
    Paganism and Pagan Survivals in Spain Up to the Fall of the Visigothic Kingdom. Catholic University of America. pp. 93–94. Retrieved
    20 March

  10. ^

    “day of preparation”, i.e. the day before Sabbath, c.f. Luke 23:54 (
    καὶ ἡμέρα ἦν Παρασκευῆς, καὶ σάββατον ἐπέφωσκεν.

  11. ^

    Copeland, Leland S. (1939). “Sources of the Seven-Day Week”.
    Popular Astronomy.
    (4): 176. Bibcode:1939PA…..47..175C.

  12. ^

    Michaelis, Anthony R. “The Enigmatic Seven”
    Interdisciplinary Science Reviews.
    7: 373.

  13. ^

    “The power of seven”.
    The Economist. 20 December 2001.

  14. ^





    Pinches, T.G. (2003). “Sabbath (Babylonian)”. In Hastings, James (ed.).
    Encyclopedia of Religion and Ethics. Vol. 20. Selbie, John A., contrib. Kessinger Publishing. pp. 889–891. ISBN978-0-7661-3698-4
    . Retrieved
    17 March

  15. ^

    Zerubavel (1989), p. 11.
  16. ^





    Senn, Frank C. (1997).
    Christian Liturgy: Catholic and Evangelical. Fortress Press. ISBN978-0-8006-2726-3.

  17. ^

    Leland, S. Copeland (April 1939). “Sources of the Seven-Day Week”.
    Popular Astronomy.
    (4): 176 ff. Bibcode:1939PA…..47..175C.

  18. ^

    A month consisted of three seven-day weeks and the fourth week of eight or nine days, thus breaking the seven-day cycle every month. Consequently, there is no evidence that the days of the week were given individual names in Babylonian tradition.
    Pinches, T.G. (2003). “Sabbath (Babylonian)”. In Hastings, James (ed.).
    Encyclopedia of Religion and Ethics. Vol. 20. Selbie, John A., contrib. Kessinger Publishing. pp. 889–891. ISBN978-0-7661-3698-4
    . Retrieved
    17 March

  19. ^

    “Each account is arranged in a series of sevens, the Babylonian in seven tablets, the Hebrew in seven days. Each of them places the creation of man in the sixth division of its series.” cited after Albert Horizon. Clay,
    The Origin of Biblical Traditions: Hebrew Legends in Babylonia and Israel, 1923, p. 74.

  20. ^

    “The Babylonian Sabbath”.
    The American Antiquarian and Oriental Journal. Vol. XXX. 1908. p. 181. Retrieved
    21 June

  21. ^

    Andreasen, Niels-Erik A. (1972).
    The Old Testament Sabbath: A Tradition-historical Investigation. Society of Biblical Literature. ISBN9780891306832.

  22. ^

    Shafer, Byron E. (1974). “Reviewed Work:
    The Old Testament Sabbath: A Tradition-Historical Investigation
    by Niels-Erik A. Andreasen”.
    Journal of Biblical Literature.
    (2): 300–301. doi:10.2307/3263102. JSTOR 3263102.

  23. ^



    Tigay, Jeffery H. (1998). “Shavua”.
    Mo’adei Yisra’el: Time and Holy Days in the Biblical and Second Commonwealth Periods (Heb.), ed. Jacob S. Licht: 22–23.

  24. ^

    Hallo, William W. (1977). “New Moons and Sabbaths: A Case-Study in the Contrastive Approach”.
    Hebrew Union College Annual.
    48: 1–18. JSTOR 23506909.

  25. ^

    Friedman, Allen (September 2008). “Unnatural Time: Its History and Theological Significance”.
    The Torah U-Madda Journal.
    15: 104–105. JSTOR 40914729, Tigay’s citation.

    {{cite journal}}: CS1 maint: postscript (link)

  26. ^

    “Japanese Days of the Week: the ‘Seven Luminaries’“.
    Days of the Week in Chinese, Japanese, Vietnamese & Mongolian. cjvlang.

  27. ^



    Keegan, Peter; Sears, Gareth; Laurence, Ray (12 September 2022).
    Written Space in the Latin West, 200 BC to AD 300. A&C Black. ISBN9781441123046.

  28. ^

    Zerubavel (1989), p. 14.

  29. ^

    So, Ky-Chun (6 April 2022).
    Jesus in Q: The Sabbath and Theology of the Bible and Extracanonical Texts. Wipf and Stock Publishers. ISBN9781498282116.

  30. ^

    Brind’Amour, Pierre (1983).
    Le calendrier Romain :Recherches chronologiques
    (in French). Editions de l’Universitá d’Ottawa. pp. 256–275. ISBN2760347028.

  31. ^

    Schaff, Philip (1884).
    History of the Christian Church Vol. III. Edinburgh: Lengkung langit&Horizon Clark. p. 380. Retrieved
    15 March

  32. ^

    Boyce, Mary (ed. & trans.).
    Textual Sources for the Study of Zoroastrianism. University of Chicago Press, 1984, p. 19-20.

  33. ^

    Genesis 1:1–2:3

  34. ^

    Landau, Judah Leo.
    The Sabbath. Johannesburg, South Africa: Ivri Publishing Society, Ltd. pp. 2, 12. Retrieved
    26 March

  35. ^

    Sampey, John Richard (1915). “Sabbath: Critical Theories”. In Orr, James (ed.).
    The International Standard Bible Encyclopedia. Howard-Severance Company. p. 2630.

  36. ^

    Strong’s Concordance,

  37. ^

    Matthew 28:1, Mark 16:2

  38. ^

    Zerubavel (1989), p. 45.

  39. ^

    Nerone Caesare Augusto Cosso Lentulo Cossil fil. Cos. VIII idus Febr(u)Arius dies solis, luna XIIIIX nun(dinae) Cumis, V (idus Februaries) nun(dinae) Pompeis
    Robert Hannah (2013). “Time in Written Spaces”. In Peter Keegan; Gareth Sears; Ray Laurence (eds.).
    Written Space in the Latin West, 200 BC to AD 300. A&C Black. p. 89.

  40. ^

    “Sahih Mukminat 2789 – Characteristics of the Day of Judgment, Paradise, and Hell – كتاب صفة القيامة والجنة والنار – Sunnah.com – Sayings and Teachings of Prophet Muhammad (صلى الله عليه و سلم)”.
    . Retrieved
    17 July

  41. ^

    Shashi, Shyam Singh (2000).
    Encyclopaedia Indica India, Pakistan, Bangladesh Vol. 76 Major dynasties of ancient Orissa: India, Pakistan, Bangladesh. Anmol Publications PVT. LTD. pp. 114–115. ISBN978-81-7041-859-7.

  42. ^

    Pandurang Vaman Kane (1930–1962).
    History of Dharmaśāstra.

  43. ^

    Neugebauer, Otto (1979).
    Ethiopic astronomy and computus. Verl. d. Österr. Akad. d. Wiss. ISBN978-3-7001-0289-2.

  44. ^

    Jayne Lutwyche (22 January 2022). “Why are there seven days in a week?”.
    Religion & Ethics. BBC.
    The Paras context of the spread of Christianity meant that Rome contributed a lot to the structure and calendar of the new faith

  45. ^

    William Francis Ryan,
    The Bathhouse at Midnight: An Historical Survey of Magic and Divination in Russia, Penn State Press, 1999 p. 380.

  46. ^

    William Francis Ryan,
    The Bathhouse at Midnight: An Historical Survey of Magic and Divination in Russia, Penn State Press, 1999 p. 383.

  47. ^

    Peter Kirby. “Saint Justin Martyr: Dialogue with Trypho”.
    Early Christian Writings.

  48. ^

    Peter Johann Haas (26 January 2002). “Weeknumber sorted by definition”.

  49. ^

    “Calendar Weeks”. J. R. Stockton. Archived from the original on 13 January 2022.

    {{cite web}}: CS1 maint: unfit URL (link)

  50. ^

    “Broadcast Calendars | RAB.com”.
    . Retrieved
    26 May

  51. ^

    “Norms and Standards in Epidemiology: Epidemiological Calendar 2000”,
    Epidemiological Bulletin, Vol. 20 No. 3, September 1999 [1]

  52. ^

    “Quality & Lead-free (Pb-free): Marking Convention”. Texas Instrument. Archived from the original on 5 April 2022.

  53. ^

    “Top Mark Convention – 4-Digit Date Code”. Fairchild Semiconductor. Archived from the original on 14 July 2022.

  54. ^

    “49 CFR 574.5 – Tire identification requirements”.
    Legal Information Institute.

  55. ^

    OED s.v. “week
    n.“, entry 1.c.: “Sometimes applied
    to other artificial cycles of a few days that have been employed various peoples”

  56. ^

    Astronomy and Basque Language, Henrike Knörr,
    Oxford VI and SEAC 99 “Astronomy and Cultural Diversity”, La Laguna, June 1999. It references Alessandro Bausani, 1982,
    The prehistoric Basque week of three days: archaeoastronomical notes,
    The Bulletin of the Center for Archaeoastronomy
    (Maryland), v. 2, 16–22. 1.
    (“week-first”, Monday), 2.
    (“week-between”, Tuesday), 3.
    (“week-last”, Wednesday).

  57. ^

    Zerubavel (1989), pp. 50–54.

  58. ^

    “Aztec calendar stone”.

  59. ^

    Zerubavel, Eviatar (1985).
    The Seven-Day Circle. New York: The Free Press. pp. 48–50. ISBN0029346800.

  60. ^

    Foss, Clive (September 2004). “Stalin’s topsy-turvy work week”.
    History Today.
    (9): 46–47.

  61. ^

    “La réforme en Russie: Il faudra attendre … berlebih de trois siècles” [The reform in Russia: It will be necessary to wait … more than three centuries].
    (in French).

  62. ^

    Zerubavel, Eviatar (1985). “The Soviet five-day
    The Seven Day Circle. New York: Free Press. pp. 35–43. ISBN0029346800.

  63. ^



    Meyer, Peter (21 February 2005). “The Hermetic Lunar Week Calendar”.
    www.hermetic.ch. Calendar Studies. Retrieved
    21 June

  • Zerubavel, Eviatar (1989).
    The Seven Day Circle: The History and Meaning of the Week. University of Chicago Press. ISBN978-0-226-98165-9.

Further reading


  • Colson, Francis Henry (1926).
    The Week: An Essay on the Origin and Development of the Seven-day Cycle. Cambridge University Press. OCLC 59110177.

  • Thomas, Northcote Whitridge (1911).
    “Week”. In Chisholm, Hugh (ed.).
    Encyclopædia Britannica. Vol. 28 (11th ed.). Cambridge University Press. p. 466.

Source: https://en.wikipedia.org/wiki/Week

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