Count unique values among duplicates - Microsoft Support
How to count the number of unique values in a range that contains duplicate values in Excel.
UNIQUE function - Microsoft Support
Learn about the UNIQUE function, which returns a list of unique values in a list or range. UNIQUE is in a class of functions called dynamic arrays.
Ways to count values in a worksheet - Microsoft Support
Watch the following video to see how to use the COUNT function and how to use the COUNTIF and COUNTA functions to count only the cells that meet conditions you specify.
Count numbers or dates based on a condition in Excel
See examples of how to use worksheet functions to count numbers or dates that fall within a range in Excel.
Count how often a value occurs in Excel - Microsoft Support
Suppose you want to find out how many times particular text or a number value occurs in a range of cells, there are several ways to count how often a value occurs.
Use the COUNTIF function in Microsoft Excel
How to use the COUNTIF function in Excel to count the number of cells that meet values you set.
COUNT function - Microsoft Support
If you want to count logical values, text, or error values, use the COUNTA function. If you want to count only numbers that meet certain criteria, use the COUNTIF function or the COUNTIFS function.
Use COUNTA to count cells that aren't blank - Microsoft Support
View an example of how to use the COUNTA function to count cells that are not empty in a range of data.
Count numbers or dates based on a condition in Excel
See examples of how to use worksheet functions to count numbers or dates that fall within a range in Excel.
Filter for unique values or remove duplicate values
Check before removing duplicates: Before removing duplicate values, it's a good idea to first try to filter on—or conditionally format on—unique values to confirm that you achieve the results you expect.