Today Function Formula in Excel

There are two other very useful Functions in Excel that take no arguments at all. These are the TODAY function and the NOW function. The TODAY Function will return the current date, while the NOW Function will return the current date and time. These can be very useful for a spreadsheet that requires having the current date and/or time. These functions are a bit different than most other Excel Functions in two ways. 

                                          Volatile & No Arguments

1. Volatile

When the term volatile is applied to an Excel Function it means that the Function is recalculated whenever Excel calculates. To understand this we need to know how, or rather when, a normal Function in Excel calculates. Most Functions in Excel will recalculate whenever any cell on which they are dependent changes. By this we mean if we have the function =SUM(A1:A10) in a cell and we changed the value of any cell within the range A1:A10 our SUM function will recalculate to reflect the change. If there was another formula in a cell that was referencing B1:B10 then it would not recalculate if we changed a cell within the range A1:A10. A volatile Function on the other hand, will recalculate whenever any formula within the entire Workbook recalculates, regardless of cell references. A workbook will also recalculate whenever we open or save.

2. No Arguments

As you are now aware, most of Excels Functions take at least one argument and others take up to 30 arguments. The TODAY and the NOW Function can take no arguments at all. What this means to the user is we simply add them to a spreadsheet like:

=TODAY()

=NOW()

In other words we enter them with empty parenthesis. As an alternative to these Functions, if you only need the current date or time then you can these shortcut keys:

Enter the date CTRL+; (SEMICOLON)

 

Enter the time CTRL+SHIFT+: (COLON)

 

This will enter the date or time as a static value. In other words they will not update, unlike TODAY and NOW. If you are creating a spreadsheet, try not to use too many volatile Functions as this can slow down recalculation. As an alternative, using the NOW Function as an example, you could place the function into a cell somewhere and then reference that cell with a simple reference like: =A1. 

We can also control the way Excel calculates by going to Tools>Options and selecting the Calculation tab. Having said this though be very careful when doing this as you can easily inadvertently feed yourself false information. This is particularly true with the option Precision as displayed. My advice is to only change from automatic calculation if you really need to and then only if you are fully aware of the consequences.