A century is a period of 100 years. Centuries are numbered ordinally in English and many other languages. The word century comes from the Latin centum, meaning one hundred. Century is sometimes abbreviated as c.[1]

A centenary is a hundredth anniversary, or a celebration of this, typically the remembrance of an event which took place a hundred years earlier.

Centuries in the Gregorian calendar[edit]

Although a century can mean any arbitrary period of 100 years, a standard century in the Gregorian calendar is a period starting on a year of which the last two digits are 01 and ending on the following year which is a multiple of 100: The 1st century was the period from 1 to 100, the 2nd century the period from 101 to 200, and so on.[2] Although, the most common way to count centuries as well as decades is to group years based on their shared digits (i.e. the 20th century is in this case referred to the period from 1900 to 1999). However, this way to count centuries is formally not correct, as these periods end on a year of which the last two digits are 99 (i.e. 1999), and these years are no multiples of 100; this would make the 1st century being the period from 1 to 99 which is not a period of 100 years. This is sometimes known as the odometer effect. The astronomical year numbering and ISO 8601 systems both contain a year zero, so the first century begins with the year zero, rather than the year one.[3]

Alternative naming systems[edit]

Informally, years may be referred to in groups based on the hundreds part of the year. In this system, the years 1900–1999 are referred to as the nineteen hundreds (1900s). Aside from English usage, this system is used in Swedish, Danish, Norwegian, Icelandic and Finnish. The Swedish nittonhundratalet (or 1900-talet), Danish nittenhundredetallet (or 1900-tallet), Norwegian nittenhundretallet (or 1900-tallet) and Finnish tuhatyhdeksänsataaluku (or 1900-luku) refer unambiguously to the years 1900–1999.

Similar dating units in other calendar systems[edit]

While the century has been commonly used in the West, other cultures and calendars have utilized differently sized groups of years in a similar manner. The Hindu calendar, in particular, summarizes its years into groups of 60,[4] while the Aztec calendar considers groups of 52.[5]

See also[edit]


  1. ^ "Oxford English Dictionary – List of Abbreviations".
  2. ^ "The 21st Century and the 3rd Millennium". aa.usno.navy.mil/. U.S. Naval Observatory. 14 June 2011. Retrieved 15 June 2018.
  3. ^ "century". Oxford Dictionaries. Retrieved 10 May 2018.
  4. ^ "www.vedavidyalaya.com". Retrieved 4 September 2013.
  5. ^ "www.aztec-history.com". Retrieved 4 September 2013.