To calculate the percentage complete for a project with a list of tasks, you can use a simple formula based on the COUNTA function. In the example shown, the formula in F6 is:
=COUNTA(C5:C11)/COUNTA(B5:B11)
How this...

To sort a list or table in random order, you can use the SORTBY function with the RANDARRAY function. In the example shown, the formula in D5 is:
=SORTBY(data,RANDARRAY(COUNTA(data)))
where "data" is the named range...

To reverse a list (i.e. put the items in a list or column in reverse order) you can use a formula based on the INDEX, COUNTA, and ROW functions. In the example shown, the formula in D5, copied down, is:
=INDEX(list,...

To creating a running count of groups of a variable size, you can use the COUNTA and CEILING function. In the example shown, C5 contains this formula:
=CEILING(COUNTA($B$5:B5)/size,1)
where "size" is the named range...

To verify that multiple cells have the same value with a case-sensitive formula, you can use a simple array formula based on the EXACT and AND functions. In the example shown, the formula in G5 is:
=AND(EXACT(B5:F5,B5...

To generate basic outline numbering you can use a formula based several Excel functions, including COUNTA, IF, MID, FIND, and LEN. In the example shown, the formula in D5 is:
=COUNTA($B$5:B5)&"."&IF(...

To create a random list of names, you can use the INDEX function and the RANDARRAY function to select random names from an existing list. In the example shown, the formula in D5 is:
=INDEX(names,RANDARRAY(10,1,1,...

If you have a list of items, and need to count how many you have total, how many are sold, how remain, etc., you can use the COUNTA function. This can be useful if you are selling tickets, seats, entries, or anything...

To count the number of cells that are blank, you can use the COUNTBLANK function. In the generic form of the formula (above) rng represents a range of cells.
In the example, the active cell contains this formula:
=...

This page shows an example of a dynamic named range created with the INDEX function together with the COUNTA function. Dynamic named ranges automatically expand and contract when data is added or removed.
In the...

To count cells that are not blank in a range, you can use the COUNTA function. In the example shown, D5 contains this formula:
=COUNTA(B5:B9)
How this formula works
COUNTA is fully automatic. When given a range of...

If you want to test a cell to see if it contains all items in a list, you can do so with a formula that uses the SEARCH function, with help from the ISNUMBER, SUMPRODUCT, and COUNTA functions.
Context
Let's say you...

To get the last relative position (i.e. last row, last column) for mixed data that contains no empty cells, you can use the COUNTA function.
In the example shown, the formula in D5 is:
=COUNTA(B4:B100)
Last *...

To generate a count with a percentage breakdown, you can use the COUNTIF or COUNTIFS function, together with COUNTA.
In the example shown the formula in H4 is:
=COUNTIF(category,F4)/COUNTA(category)
How this formula...

To count unique values in a set of data, you can use the UNIQUE function together with the COUNTA function. In the example shown, the formula in F5 is:
=COUNTA(UNIQUE(B5:B16))
which returns 7, since there are seven...