What is a century and how do you work out what century you are in?

We measure and record passage of time using different units of time such as hours, days, weeks, months and years.

A day is the time taken by the Earth for one complete revolution around its axis. An year is the time taken by the earth for one complete rotation around the sun. This equal to 365 days, 5 hours, 48 minutes and 46 seconds.

In the past, different countries have devised different calendars to measure and record time. Some of these calenders are still used by some people in a limited. But the most widely used calender, which is also the internationally accepted common calendar, is the Gregorian calendar devised in 1582. Some corrections were made in this calendar to take into account the improved measurement of period of days and year with advancement of science.

In this calendar the counting of years is supposed to start from the year of birth of Jesus Christ. As per this calendar the current year going on is year 2009.

Century refers to blocks of hundred year periods starting from January 1 of year 1, and continuing up to December 31 of year 100. The second century started immediately in completion of first century and ended on December 31, 200. The twentieth century started on January 1, 1901, and ended on December 31, 2000.

It will not be out of place to point out that many companies projected the day January 1, 2000 as the start of the twenty-first century, but that is not the real start of twenty-first century. These companies projected that as start of twenty-first century, perhaps in their hurry to to use this event as an occasion to make extra money by organizing events to celebrate it, and by linking marketing of their products to this occasions.