Is year 2000 a leap year?

Quick question, is the year 2000 a leap year? A suprising number of people give the wrong answer. The correct answer is "yes", that is 2000 is a leap year. Why do so many folks give the wrong answer to this simple question? In general, a year is a leap year if it is evenly divisible by 4. Most people also remember the exception which is a year is not a leap year if it ends in "00" (ie., the year is even divisable by 100). So years like 1972, 1980, and 1996 are leap years, but 1800 and 1900 are not.

So why then is a 2000 a leap year? What many folks do not realize is that the 100 year exception itself has an exception. Years that are evenly divisable by 400 are leap years. So 2000 as well as 2400 will be leap years.

Programmers who write date conversion code and don't know about the "exception to the exception" will end up creating software which will display incorrect dates starting Feb. 29th, 2000. The incorrect conversions software will instead give Feb. 29th as March 1. Even worse, all subsequent dates will likely be off by one day also.

Although the Leap Year 2000 bug is not technically the same as the Y2K bug, it is many times lumped together Y2K bug because it occurs so close to Jan. 1, 2000.

Over the years, operating systems and development tools have shipped with the "Leap Year 2000" bug in them. This means that applications that use these broken operating systems or tools will also have the bug. However, over the last 5 years with the all of the talk of the Y2K bug, most of the problems have been fixed.