Auto Generate Dates

Hi All,

I am currently working a excel formula to input a Revision_Date in column A then it will auto generate the number of days per month(only weekdays) on column B(January), column C(February) and so on depending on the current date. Example if today is April 17, 2017 and my input in Column A is Feb 13, 2017, it will compute number of days from Feb 13 to Feb 28 (which is 12 days) to be generated on Column C(Feb). Then on March which is complete since it covers the whole month until today on Column D(Mar). Then comes to April to compute the days from April 1 to April 16 on Column E(Apr). Can someone help me as I am really not familiar with excel. Hoping someone can share any formulas/techniques on how to do it. Thanks in advance.