Listed below is master list of date & time functions available in Google Spreadsheet.
TODAY – Displays the current date
DATE – Converts the entered day, month and year in to a Date.
DATEVALUE – Display the entered text in quotes as Date.
DAY – Displays the Day as integer for the given Date Value.
DAYS360 – Returns the difference between the two dates.
EDATE – Returns the date with number of months added to the Start date. The months can be also be in negative.
EMONTH – This would return the last day of the month for the date that is month away from the start date.
TIME – Returns the Time value for the entered hours, minutes and seconds.
HOUR – Returns the hour for the given time value.
MINUTE – Returns the minute for the given time value.
MONTH – Returns the month for the give date value.
NETWORKDAYS – Returns the number working between entered start date and end date. It also accepts an optional third parameter to specify the list of holidays.
NOW – Returns the current system date and time.
SECOND – Returns the second for the given date & time or just time value.
WEEKDAY – This would return the weekday of the give date value. You have option of specifying the start of the weekday. In the example below the weekday is starting on Monday.
YEAR – Returns the year for the given date value.