# Count Unique Values

This example shows you how to create an array formula that **counts unique values**.

1. We use the COUNTIF function. For example, to count the number of 5’s, use the following function.

2. To count the unique values (don’t be overwhelmed), we add the SUM function, 1/, and replace 5 with A1:A6.

3. Finish by pressing CTRL + SHIFT + ENTER.

Note: The formula bar indicates that this is an array formula by enclosing it in curly braces {}. Do not type these yourself. They will disappear when you edit the formula.

Explanation: The range (array constant) created by the COUNTIF function is stored in **Excel’s** memory, not in a range. The array constant looks as follows:

{3;1;1;1;3;3} – (three 7’s, one sun, one moon, one 5, three 7’s, three 7’s)

This reduces to:

{1/3;1/1;1/1;1/1;1/3;1/3}

This array constant is used as an argument for the SUM function, giving a result of 1/3+1+1+1+1/3+1/3 = 4.

4. The array formula below counts the number of values that occur exactly once.

Explanation: the IF function converts the array constant {3;1;1;1;3;3} to {0;1;1;1;0;0}. This array constant is used as an argument for the SUM function, giving a result of 3.

5. If you have Excel 365 or Excel 2021, simply use the magic UNIQUE function to extract unique values.

Note: this dynamic array function, entered into cell C3, fills multiple cells. Wow! This behavior in Excel 365/2021 is called spilling.

6. Next, add the COUNTA function to count unique values in Excel 365/2021.

7. The formula below counts the number of values that occur exactly once.

Note: the UNIQUE function has 2 optional arguments. The default value of 0 (second argument) tells the UNIQUE function to extract values from a vertical array. The value 1 (third argument) tells the UNIQUE function to extract values that occur exactly once.

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