COUNT scans each argument and increments a counter for every cell that contains a number. Cells containing text strings are skipped. Blank cells are skipped. Cells containing TRUE or FALSE (logical values) are skipped. Dates are counted because Excel and Google Sheets store them as serial numbers internally -- a date is a number with a date format applied. Cells containing errors like #N/A or #DIV/0! are also skipped. When passed literal values rather than ranges, COUNT counts each numeric literal -- =COUNT(1,2,"three") returns 2 because "three" is text. The most important distinction to understand is COUNT versus
COUNTA: COUNTA counts everything that is not blank, while COUNT counts only numbers. For conditional counting based on a criterion, use the
COUNTIF function. For counting blank cells specifically, use
COUNTBLANK. COUNT handles multiple ranges in one formula by listing them as comma-separated arguments.