By Ken Bluttman

Most Excel functions take inputs — called arguments or parameters — that specify the data the function is to use. Some functions take no arguments, some take one, and others take many; it all depends on the function. The argument list is always enclosed in parentheses following the function name. If there’s more than one argument, the arguments are separated by commas. Look at a few examples:

Function Comment
=NOW() Takes no arguments.
=AVERAGE(A6,A11,B7) Can take up to 255 arguments. Here, three cell references are
included as arguments. The arguments are separated by commas.
=AVERAGE(A6:A10,A13:A19,A23:A29) In this example, the arguments are range references instead of
cell references. The arguments are separated by commas.
=IPMT(B5, B6, B7, B8) Requires four arguments. Commas separate the arguments.

Some functions have required arguments and optional arguments. You must provide the required ones. The optional ones are, well, optional. But you may want to include them if their presence helps the function return the value you need.

The IPMT function is a good example. Four arguments are required, and two more are optional.