# Excel Date Formula

Have you ever entered a project due date into a spreadsheet by manually counting the number of days and typing in the number? If so, then you’ve also experienced the tedium of recalculating those dates by hand and retyping them.

Fortunately, Excel has all the functions to do the date arithmetic for you.

Entering a Date with the Year, Month and Day

To enter a specific date in your spreadsheet use the DATE(year,month,day) function. Entering:

=DATE(2014,12,15)

returns the date December 15, 2014.

Using the Current Date

To enter the current date, use the dynamic TODAY() function. TODAY() does not require any arguments; it always returns the current date.

You can combine this with the DATE() function. If your project is due on November 10, 2014, count the number of days left before the due date by typing, “=DATE(2014,11,10)-TODAY()”.

Remember: Excel updates the value of TODAY() every time it recalculates your spreadsheet. If you want to save the date that you updated a section of your sheet, type in the date instead of using TODAY().

To add a number of days to a date, or to subtract a number of days from a date, just add or subtract the number of days. You don’t need any special functions.

In this example:

• “=A1+10” returns December 25, 2014, which is ten days after December 15.
• “=A2-3” returns December 7, 2014, which is 3 days before December 10.
• =”A3+365” returns December 15, 2014, which is 365 days after December 15, 2013.

Note that the number that you add or subtract is always the number of days. You cannot substitute months or years.
Similarly, you can subtract two dates to get the number of days between them.

• “=A1-A2” returns 5, because December 10 is five days before December 15.
• “=A1-A3” returns 365, because December 15, 2013 is one year (365 days) before December 15, 2014.
• “=A2-A3” returns 360, because December 15, 2013, is 360 days before December 10, 2014.

Try it yourself. Type a date into a cell, and practice adding and subtracting numbers of days from it to get the expected results.