How to Use SQRT Function in Excel: Simple Guide

In Excel, use the SQRT function to find the square root of a positive number. Enter =SQRT(number) in a cell, replacing number with the value or cell reference you want to calculate.

Syntax

The SQRT function in Excel calculates the square root of a number. It takes one argument:

• number: The positive number or cell reference you want the square root of.

If the number is negative, Excel will return an error.

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=SQRT(number)

Example

This example shows how to calculate the square root of 25 and a value in cell A1.

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=SQRT(25)
=SQRT(A1)

Output

5
(square root of the value in A1, e.g. if A1=16, output is 4)

Common Pitfalls

Common mistakes when using SQRT include:

• Using a negative number, which causes a #NUM! error.
• Forgetting to use the equal sign = before the function.
• Passing text or empty cells, which can cause errors or unexpected results.

Always ensure the input is a positive number or a valid cell reference.

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=SQRT(-9)  (returns #NUM! error)
=SQRT("text")  (returns #VALUE! error)
=SQRT(16)  (correct usage, returns 4)

Output

#NUM!
#VALUE!
4

Quick Reference

Function	Description	Example	Result
=SQRT(number)	Returns square root of number	=SQRT(9)	3
=SQRT(A1)	Square root of value in cell A1	A1=16	4
=SQRT(-4)	Negative input causes error	Returns	#NUM!

Key Takeaways

Use =SQRT(number) to find the square root of a positive number in Excel.

Input must be a positive number or valid cell reference to avoid errors.

Negative numbers cause a #NUM! error in the SQRT function.

Always start formulas with an equal sign (=) in Excel.

SQRT only takes one argument: the number you want the square root of.