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The Seven Days of the Week

The seven-day week is the International Standard week (ISO 8601) used by the majority of the world.

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Calendars help keep track of the days

The seven-day-week is used world-wide, but week numbers only in some places.


Starts Monday Or Sunday

According to International Standard ISO 8601, Monday is the first day of the week followed by Tuesday, Wednesday, Thursday, Friday, Saturday, and with Sunday as the seventh and final day.

Although this is the international standard, several countries including United States and Canada put Sunday at the start of the week.

Named for Gods and Planets

Most Latin-based languages derived the names of the seven days of the week from the Roman calendar where they related each day of the week with seven celestial bodies; the Sun, the Moon, Mercury, Venus, Mars, Jupiter, and Saturn.

The English language has retained these names for Saturday, Sunday, and Monday, however the planet names for the other days of the week were replaced by their equivalent Norse or Germanic gods.

Some Asiatic languages such as Hindi, Japanese and Korean have a similar relationship between the week days and the planets.

Babylonian Origins

The seven-day-week provides a clear method of representing dates and times to avoid misinterpretation between people from different countries with varying traditions for writing numeric dates and times.

There are many different opinions as to how the seven-day week originated, but the most common explanation is that the seven-day week seems to have originated when Babylonian astrologers assigned planet gods to the days of the week around 700 BCE. The Romans later replaced these names with their own planet gods and Germanic and Norse people later did the same with some of their own gods.

When Is the Weekend?

As the first day of the week varies in different cultures, so does the weekend. The Christian or Western world marks Sunday as their day of rest and worship, while Muslims refer to Friday as their day of rest and prayer. The Jewish calendar counts Saturday– the Sabbath–as the day of rest and worship.

Both Saturdays and Sundays are common days of rest on the calendar, some countries use a separate color for the weekends and reserve the black or grey fonts for the weekdays, Monday-Friday.

52 Weeks & 1 Day

A common year roughly adds up to 52 weeks of seven days each plus one day or two, if it's a leap year. However, countries vary on exactly how they present and number the weeks in their calendars.

Some Years Have 53 Weeks

The weeks of the year in a Gregorian calendar are numbered from week 1 to week 52 or 53, depending on varying factors. These week numbers are commonly used in some European and Asian countries; but not so much in the United States.

Topics: Weekdays, Calendar, Dates

In This Article


Create Calendar With Holidays

The 12 Months of the Year

  1. January
  2. February
  3. March
  4. April
  5. May
  6. June
  7. July
  8. August
  9. September
  10. October
  11. November
  12. December

Months of the Year

When Is the Next Occurrence Of


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