The two most easily available ways to calculate what day a specific date falls on are to either construct a perpetual calendar online or mentally calculate the day. The mental calculation method is called The Marais Formula. Online calculators are numerous, free and come in a number of different formats.
The Marais Formula is relatively complex and difficult to learn, but may be used to impress friends. Online date calendars are much easier to use and can give a straight answer to what day a specific date falls on by inputting the year and the month. Other online calendars allow users to print a blank perpetual calendar, using a distinct starting point for that year. It is also possible to construct a movable paper perpetual calendar. By far the easiest way is to use one of the online calculators noted, particularly the Penn State calculator or the Word templates calendar.