Q:

Converting decimal dates to calendar dates?

I have the decimal number 2005.067 which represents the date January 25, 2005. The math equation below shows how the decimal number is created 2005 + (25 - 0.5)/365. I want to be able to grab 2005.067 and convert it back to January 25, 2005.

January 25, 2005 (Day 25) = 2005 + (25 - 0.5)/365 =2005.067

I don't have that great of an understanding of math to be able to figure it out so any help would be greatly appreciated.

A:

Use $$((x-2005)\times365)+.5\\\text{or}\\((x-\text{year})\times365)+.5$$ to get what day of the year it is.  For example, 25 in this case.
$$\begin{align}((2005.067-2005)\times365)+.5&=0.067\times365+.5\\&\approx25\end{align}$$

