Excel's NOT function

Once you've got a solid handle on Excel's TRUE, FALSE, AND, and OR functions, there's only one more logical structure to learn: NOT. Let's take a look at how it works.

Using NOT

The NOT function is the easiest to remember of Excel's logical formulas. Here's the formula:

=NOT(logical_expression)

NOT takes whatever logical expression is inside of it, and spits out the reverse. In other words, if the logical_expression inside of NOT is TRUE, the formula will output FALSE; and, conversely, if the logical_expression inside of NOT is FALSE, the formula will output TRUE.

Let's take a look at a couple of examples:

=NOT(TRUE)
Output: FALSE

=NOT(FALSE)
Output: TRUE

The above formulas are very simple: the NOT function just reverses whatever logical_expression we give it. But, NOT will also work with more complex expressions. Here's an example:

=NOT(OR(7>3, "Cookies"="Brownies"))
Step 1: =NOT(OR(TRUE, FALSE))
Step 2: =NOT(TRUE)
Output: FALSE

We can also use NOT within AND and OR functions, like so:

=AND(9>5, NOT(8<1))
Step 1: =AND(TRUE, NOT(FALSE))
Step 2: =AND(TRUE, TRUE)
Output: TRUE

Use NOT to simplify boolean logic when you want to check to ensure that a particular condition is not true — for example, if you wanted to make sure that the amount charged on an invoice does not exceed a particular threshold.

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