The COUNTIF function counts the number of cells

The COUNTIF function counts the number of cells within a given range that meet a given criteria.

Syntax
COUNTIF(range,criteria)

Range: The range of cells from which you want to count cells.

Criteria: The criteria upon which you want to base your count. It defines which cells will be counted.
The criteria can b a number, expression, cell reference, or a text.

Examples:

=COUNTIF(B15:B33;”>100″)
=COUNTIF(A1:A8;”ABC”)

The examples below show how to use COUNTIF with numeric values. A1 to A6 is our data range. In rows 7, 8 and 9 you have the text of the formula  in column A (for explanation only), the actual formula in column B and column C shows which cells are qualified to be counted.

COUNTIF and wildcards

You can use the wildcard characters question mark (?) and asterisk (*) in the COUNTIF criteria. A question mark matches any single character; an asterisk matches any sequence of characters.