Commonly used functions I use for DAX date and time functions including Count of Days in Current Year,
me@jaykilleen.com wrote this about 7 years ago and it was last updated about 7 years ago.
Insert these as measures or use in formulas for new columns in a DAX table
For these examples TODAY() = 07/04/2017
DaysThisYear = DATEDIFF(DATE(YEAR(TODAY()),1,1),DATE(YEAR(TODAY())+1,1,1)-1,DAY)+1 // returns 365
DaysThisFinancialYear = DATEDIFF(DATE(YEAR(TODAY()),7,1),DATE(YEAR(TODAY())+1,7,1)-1,DAY)+1 // returns 365_
DaysElapsedThisYear = DATEDIFF(DATE(YEAR(TODAY()),1,1),TODAY(),DAY)+1 // returns 97
LastDayOfThisMonth = FORMAT(EOMONTH(TODAY(),0),"DD") // returns 30