Summary

The Excel IMABS function returns the absolute value of a complex number.

Purpose 

Get the absolute value of a complex number

Return value 

The absolute value of a complex number

Syntax

=IMABS(inumber)
  • inumber - The string representing a complex number.

How to use 

The Excel IMABS function returns the absolute value of a complex number. For example:

=IMABS("4+3i") // returns 5
Excel handles complex numbers as strings formatted like "x+yi" or "x+yj". Use the COMPLEX function to get the string representing a complex number.

Explanation

The absolute value of a complex number goes by several other names: modulus, length, or magnitude. All of them refer to the same thing. When we draw the arrow representing a complex number, the absolute value is equal to the distance from the origin to the tip of the complex number.

The absolute value of a complex number.

The IMABS function always returns a positive number. For example, consider the complex number "-12-5i" which points in a different direction.

The absolute value of a complex number pointing in a different direction.

The absolute value of this complex number is positive 13.

=IMABS("-12-5i") // returns 13

In general, the absolute value of a complex number "z=x+yi" is given by the formula below.

=SQRT(x^2 + y^2)

Notes

  • IMABS returns a #NUM error when the input does not represent a valid complex number.

Images courtesy of wumbo.net.

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Dave Bruns

Hi - I'm Dave Bruns, and I run Exceljet with my wife, Lisa. Our goal is to help you work faster in Excel. We create short videos, and clear examples of formulas, functions, pivot tables, conditional formatting, and charts.