Introduction | Example | Tutorial | Applications | Comments

## Introduction - Square Root in VBA

This VBA tutorial shows you how to take the square root of a number in VBA using the Sqr function. The VBA Sqr function accepts one argument - a positive number - and will return the square root of that number as a Double data type.

Let’s take a look at an example.

## Example - Square Root in VBA

### VBA Sqr Function

``````Sub VBA_Square_Root()
Dim d1 As Double
Dim d2 As Double

d1 = 144
d2 = Sqr(d1) 'Returns 12
Debug.Print d2
End Sub``````

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## Tutorial - Square Root in VBA

### How to find the square root in VBA

The VBA Sqr function returns the square root of a number. The Sqr function accepts one argument: a positive number. Here’s the syntax for the Sqr function:

`Sqr(Number)`

In the example above, the “Number” argument is 144 so the value of d2 is 12 since 12x12=144.

### Common Errors with the Sqr function

Like I said earlier, the Sqr function accepts a positive number. Any number multiplied by itself returns a positive number so, ignoring imaginary numbers, you can’t take the square root of a negative number.

Because of that, the VBA Sqr function will produce a “Run-time error ‘5’ Invalid procedure call or argument” error when attempting to take a square root of a negative number. Similarly, you will get a “Run-time error ‘13’ Type Mismatch” error when you try to take the square root of something that isn’t a number. With that said, the Sqr function isn’t dumb. If you try to take the square root of a string that represents a number, it will properly process the string as a number and return the square root. Here’s an example to demonstrate what I mean:

``````Sub VBA_Square_Root_String()
Dim val1 As String
Dim val2 As String

val1 = "16"
val2 = Sqr(val1) 'Returns "4"
Debug.Print val2
End Sub``````

The result of applying the square root function in this example is a string with a value of “4.” If the variable val2 was instead declared as a double, the VBA square root function would be smart enough to process the string “16” as a number and return a double with a numeric value of 4.

## Application Ideas

You’ll want to use the Sqr function anytime you need to calculate the square root in VBA.

It’s wise to use the Sgn function to test for a positive number or the Abs function to return the absolute value of your number before passing it as an argument to the VBA Sqr function.

## Closing Thoughts

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