Which Excel function is used to count the number of cells that meet a specific condition?

The function COUNTIF() is specifically designed to count the number of cells that meet a specific criterion or condition within a designated range. It takes two arguments: the range of cells to evaluate and the condition that determines which cells to count. For example, if you wanted to count how many times the value "apple" appears in a list of fruits, you would use COUNTIF(range, "apple").

In contrast, the other functions serve different purposes. SUMIF() is used to sum up the values in a range that meet a specific condition rather than counting them. AVERAGEIF() calculates the average of the values that meet a specific condition, which also differs from merely counting the relevant cells. INDEX() provides a way to retrieve the value of a cell at the intersection of a specified row and column in a range, unrelated to counting or conditions. Thus, COUNTIF() is the appropriate function for counting cells based on specific criteria.