Counting cells that contain any value (cells that are not empty)

The COUNTA function is a bit more specialized than some of the other tools found in Excel. It will do a count of all cells in any given selection to determine how many of them have any content at all.

Basically, if a cell is not empty, it will be included in the COUNTA result.

You will need to type the basic tags for the formula yourself, but Excel will allow you to select the cells you need with the mouse instead of having to enter them manually with the keyboard. You can also press the CTRL key when selecting non-contiguous cells and add them to your group from all over the spreadsheet.
Close the parentheses and hit Enter to get your populated cell count.