The Excel COMPLEX function creates a complex number with given real and imaginary coefficients. COMPLEX returns a text result in the form x + yi or x + yj.


Convert coefficients to complex number

Return value 

Complex number as text


  • real_num - The real number.
  • i_num - The imaginary number.
  • suffix - [optional] The suffix, either "i" or "j".


=COMPLEX(real_num, i_num, [suffix])

Usage notes 

A complex number has two parts: a real number and an imaginary number. The COMPLEX function converts real and imaginary coefficients into a complex number of the form x + yi or x + yj, where x represents the real number and y represents the imaginary number. For example:

=COMPLEX(5,3) // returns 5+3i

To use the "j" instead of "i":

=COMPLEX(5,3,"j") // returns 5+3j

In the example shown, the formula in E6 is:



  1. If omitted, suffix defaults to "i".
  2. suffix must be lowercase "i" or "j"; other values result in a #VALUE error.
  3. If real_num or i_num are nonnumeric, COMPLEX returns the #VALUE! error.
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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.