Google Sheets | COUNTA & COUNTUNIQUE Functions to Check for Duplicate Data | Example | Tutorial

In Google Sheets, a way to check for duplicate data is to use the
COUNTA and COUNTUNIQUE functions. Whereas COUNTA counts unique and duplicate numeric and alphabetic data in the specified range(s), COUNTUNIQUE counts only unique values in the specified range(s).

If the difference between the values returned by COUNTA and COUNTUNIQUE is zero, then there is no duplicate data. Otherwise, the number of duplicate data equals the said difference.

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Google Sheets Quiz with Demo of Answers

Try this 5-question quiz, which also demos the answers. The quiz
can be helpful in your day-to-day spreadsheet work or for job interview:

https://youtu.be/rlcc03qQfcI

COUNTA Function

COUNTA counts unique and duplicate numerical or alphabetical data in the specified ranges. This is the link
to the step-by-step tutorial:

https://youtu.be/kFIOgmZdnL4

COUNTUNIQUE Function

COUNTUNIQUE counts unique data in the specified ranges. Here is the link
to the step-by-step tutorial:

https://youtu.be/tBiC5h24QZw
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Here are the formats of the COUNTUNIQUE and COUNTA function formulas. For more info on these two functions, please refer to their separate tutorials, whose links are given above.

COUNTA Function Formula

=COUNTA(value1, [value2], […])

COUNTUNIQUE Function Formula

=COUNTUNIQUE(value1, [value2], […])

Assume that the data is in the range A2:A15.

Here is the COUNTA and COUNTUNIQUE functions combo formula:

=COUNTA(A2:A15)-COUNTUNIQUE(A2:A15)

If the difference between the values returned by the two functions is zero, it
means there is no duplicate data in the specified range. Otherwise, the number of duplicate entries equal the difference between the two values.

Take a look at this video tutorial, which gives the steps to check for duplicate data in a range, using the Google Sheets COUNTUNIQUE and COUNTA functions, with an example.