Nestled away amongst a pile of recently updated pages on Microsoft's Learn site, which contains product documentation and technical resources, was a curiously titled article: "Excel incorrectly assumes that the year 1900 is a leap year." I thought that can't be right, surely everything would have fallen over long ago, but it turns out that this problem has long been known about among Excel-fanciers and Microsoft is never going to fix it: because then everything would collapse.
"When Lotus 1-2-3 was first released, the program assumed that the year 1900 was a leap year, even though it actually was not a leap year," reads the Microsoft explanation. "This made it easier for the program to handle leap years and caused no harm to almost all date calculations in Lotus 1-2-3."
