How to Calculate a Square Root in Excel with SQRT

Use SQRT for real layouts: the side of a square from its area, a diagonal from two sides, a radius from an area.

You will learn to

• Find a side length from an area
• Find a diagonal with Pythagoras
• Find a circle’s radius from its area

How it works

SQRT(number) returns the positive square root: =SQRT(30.25) is 5.5, so a 30.25 m² square patio is 5.5 m on each side. Combine it with squares for Pythagoras — =SQRT(C4^2+D4^2) gives the diagonal of a rectangle — or with PI() to get a circle’s radius from its area.

SQRT of a negative number returns #NUM!. If your input might be negative (such as a difference), wrap it in ABS first or check the sign. =x^(1/2) gives the same result as SQRT if you prefer the operator.

=SQRT(B3)