By SCCount formula in excel will count the numbers present in the cell of the selected data whereas counta formula will count the number of cells that contains data.as shown below in image.
In below image both formulas are applied to first column and we can see count function does not count the first row in column A i.e Numbers which is not numeric and counta formula output counts the data present in all cells of column A.
Example of Count and Counta in Excel
