- Amit Sarda

# Counting Unique Values in a List

Updated: Dec 21, 2019

**Problem and Dataset**

I recently had a client who wanted a quick way to count the number of unique values in a list. In the following case, the number of unique names in the data in column A.

**Formula**

The general format of the formula is:

`=SUMPRODUCT(1/COUNTIFS(data,data))`

**How it Works**

The trick is in knowing how the formula actually works.

If you evaluate the formula, this is what you get:

`=SUMPRODUCT(1/{7;7;7;7;7;1;7;7;1;2;2})`

The formula counts the number of instances of each name in the list (7; 7; 7; ….), and stores the count in an array.

1/Array creates fractions for each value in the list.

SUMPRODUCT then sums up the fractions for each name (7*1/7, 2*1/2, etc.) and gives you the number of 1s in the calculation.

Genius, I say!