Millennia to Centuries (ky to c)

1 millennium equals 10 centuries exactly.

1 millennium = 10 centuries

How to convert millennia to centuries

To convert millennia to centuries, multiply the number of millennia by 10. This factor is exact. To go the other way, multiply centuries by 0.1.

centuries = millennia × 10

Example: 10 millennia = 100 centuries.

Months and years are not constant. This site uses the average Gregorian year of 365.2425 days, so one 'year' converts to 365.2425 days, not 365; use 'common year' for exactly 365 days.

About these units

Millennium (ky)

CalendarCurrent unit

One thousand years.

Latin supplied the parts of millennium: mille, a thousand, and annus, a year. The plural can be millennia or millenniums. Because a thousand years exceeds any one person's reach, the word acquired religious overtones in the idea of millenarianism, though the unit itself is a plain count of years. When the year 2000 arrived, a new question came with it: was this the start of the third millennium, or was that a year away?

A millennium is 1,000 years, here 1,000 average Gregorian years. The 2001 camp points out that there is no year zero, so the first millennium ran from year 1 to year 1000. The 2000 camp followed the odometer effect, in which the hundreds and thousands digits roll over together. Most people celebrated in 2000, and the celebrations in 2001 were mostly routine, although the U.S. Naval Observatory, Cuba and Japan did mark the strict date. The evolutionary biologist Stephen Jay Gould observed that the strict view dominated at the start of the 20th century and the popular view at its end.

1 millennium = 31,556,952,000 seconds (exactly).

Sources: Wikipedia: Millennium; Wikipedia: Millenarianism

Century (c)

CalendarCurrent unit

One hundred years.

From Latin centum, a hundred, century has meant a hundred of many things. For time it became popular as a way to speak about a span longer than a lifetime can easily contain, and some languages organise history around it: Italian uses terms like Quattrocento for the 15th century, and Swedish writes 1900-talet for the years 1900 to 1999. Whether such a century starts at year 00 or year 01 is an old argument.

A century is 100 years, which here means 100 average Gregorian years. The strict view counts from year 1, because the AD calendar has no year zero, so the 1st century AD ran from AD 1 to AD 100 and the 21st century covers 2001 to 2100. The popular view groups years by their hundreds digit, making the 20th century 1900 to 1999. The Gregorian calendar itself treats century years specially, since 1700, 1800 and 1900 were not leap years while 1600 and 2000 were.

1 century = 3,155,695,200 seconds (exactly).

Sources: Wikipedia: Century; Wikipedia: Gregorian calendar

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