A millennium (plural: millenniums or millennia) is a measure of time. 1 millennium spans a period of 1000 years. A millennium can refer to any period of 1000 years. In the Gregorian calendar, the most widely used calendar in the world, the first millennium started in the year 1 and ended in the year 1000. The second millennium started in the year 1001 and ended in the year 2000. Currently, based on the Gregorian calendar, we are in the 3rd millennium, which will last long past the end of our lives up until the year 3000.

A millennium is a larger span of time than people can really relate to. Below are some conversions of a millennium to other commonly used measurements of time.


Convert the following periods of time into millennia.

1. 15 centuries:

15/10 = 1.5 millennia

2. 728,500 days:

728,500/365,250 = 2 millennia

3. 24 hours:

24/8,766,000 = 0.00000274 millennia

Did you know?

There is a set of seven mathematics problems known as the Millennium Prize Problems. Anyone who can solve one of these problems will be rewarded with $1,000,000. Only 1 of the 7 problems has been solved thus far.

The questions were chosen by the Clay Mathematics Institute in the year 2000, the last year of the 2nd millennium in the Gregorian calendar. The reward is also provided by the Clay Mathematics Institute, whose challenge has successfully motivated researchers to attempt to solve these wide-ranging mathematical problems in the areas of theoretical computer science, physics, number theory, algebraic geometry, and topology.