How To Use The Excel Function ISBLANK To Test If A Cell Is Empty

Written by co-founder Kasper Langmann, Microsoft Office Specialist.

There are many “IS-based” functions available in Microsoft Excel. One of those is the ISBLANK function.

This function checks whether a reference is to an empty cell, and then returns either a TRUE or FALSE value.

In this article, we will dig into the details of how to use ISBLANK.

Kasper Langmann, Co-founder of Spreadsheeto


The syntax for ISBLANK is simple.

The syntax of the ISBLANK function


There is a single required argument: value.

If the value argument does not refer to a cell reference, it will return the #VALUE error.

You can use ISBLANK to check for holes or gaps in user input.

As we will see a bit further in our discussion, we can use the results of ISBLANK within another formula like an IF.

ISBLANK will determine that a cell is empty only if if contains nothing.

This is important to be aware of since cells that contain spaces or empty strings are not actually empty.

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Example 1: basic concept

In our first example, we have a couple of cells that contain data and one that contains nothing. In column B, we have our ISBLANK formula results.

As we would expect, the formulas referring to the cells containing data return FALSE.

Then the formula referring to the blank cell returns TRUE. In column C, you can see the actual formulas for each row.


Example 2: managing references with spaces and empty strings

Cells that contain spaces or empty strings appear blank to the naked eye. ISBLANK can be helpful in detecting the presence of spaces and empty strings in cells.

In the following example, we again have a column with values. We also have a column containing ISBLANK formulas to check those cell references.


Note the FALSE values in the formula results for rows 4 and 5 in the table.

These are examples of cells that appear blank but are not empty.

Kasper Langmann, Co-founder of Spreadsheeto

A4 actually contains spaces while A5 contains an empty string (“”).

Cell A6 is empty and so the ISBLANK formula results in TRUE. This emphasizes the value of ISBLANK since it appears that cells A4, A5, and A6 are all empty.

But, we now know this not to be true after testing those cells with ISBLANK.

Example 3: practical use of ISBLANK

There is more to ISBLANK than being able to check whether cells that appear blank actually are empty. Let us look at a more practical use of the function.

Remember we mentioned the TRUE or FALSE values returned by ISBLANK can be very useful with an IF formula.

We can apply this to a scenario where we want to determine schedule availability.

We will leverage the logic of an IF formula to return a custom output that we choose. If you are unfamiliar with the IF function, the syntax is simple and straigtforward.

=IF(logical_test, [value_if_true], [value_if_false])

It tests some logical statement to be true or false. In contrast to ISBLANK, it allows us to dictate what condition we want to test. In our case, that test is our ISBLANK formula.

For example, the first step to building our formula here will look something like this:


We simply place the ISBLANK formula in the logical_test argument of the IF formula. So, we are testing the cells in a column where names get placed in time slots on a student advising schedule.

If the cell already contains a name, we simply want the corresponding field in the Availability column to be blank.

If a cell for a given time slot in the Name column is empty, we want the cell in Availability to say Open.

All that remains to do is finish out the formula we began creating for testing cell B4:


Once we copy our formula down, we get something that looks like the following figure.



What started out appearing as a mundane function turns out to be quite useful in the right scenario.

This is true for many of the built-in functions available in Excel. Alone they are so simple that it can be a challenge to understand their practical usefulness.

Yet, these simple functions become more powerful by using them with other formulas.

Our Weekly Student Advising Schedule example is simple. But it drives home the utility of ISBLANK used within another formula.

Kasper Langmann, Co-founder of Spreadsheeto

This is the point: to think about solutions to challenges. This can lead you to creative ways to solve problems and get the most out of the simplest functions.