Date Calculation

Today I learned that Excel incorrectly assumes 1900 was a leap year, and Microsoft will never fix it because the whole…

Microsoft's Excel spreadsheet software incorrectly assumes the year 1900 was a leap year, a bug inherited from Lotus 1-2-3. While technically possible to fix, Microsoft will not address the issue due to the significant compatibility problems and data corruption it would cause for existing users and formulas. This long-standing bug is considered rare in its impact, affecting only dates before March 1, 1900.