# COMPLEX function: Description, Usage, Syntax, Examples and Explanation

## What is COMPLEX function in Excel?

COMPLEX function is one of Engineering functions in Microsoft Excel that converts real and imaginary coefficients into a complex number of the form x + yi or x + yj.

## Syntax of COMPLEX function

COMPLEX(real_num, i_num, [suffix])

The COMPLEX function syntax has the following arguments:

**Real_num:**The real coefficient of the complex number.**I_num:**The imaginary coefficient of the complex number.**Suffix (Optional):**The suffix for the imaginary component of the complex number. If omitted, suffix is assumed to be “i”.

**Note:** All complex number functions accept “i” and “j” for suffix, but neither “I” nor “J”. Using uppercase results in the #VALUE! error value. All functions that accept two or more complex numbers require that all suffixes match.

## COMPLEX formula explanation

- If real_num is nonnumeric, COMPLEX returns the #VALUE! error value.
- If i_num is nonnumeric, COMPLEX returns the #VALUE! error value.
- If suffix is neither “i” nor “j”, COMPLEX returns the #VALUE! error value.

## Example of COMPLEX function

Steps to follow:

1. Open a new Excel worksheet.

2. Copy data in the following table below and paste it in cell A1

Note: For formulas to show results, select them, press F2 key on your keyboard and then press Enter.

You can adjust the column widths to see all the data, if need be.

Formula |
Description |
Result |

=COMPLEX(3,4) | Complex number with 3 and 4 as the real and imaginary coefficients | 3+4i |

=COMPLEX(3,4,”j”) | Complex number with 3 and 4 as the real and imaginary coefficients, and j as the suffix | 3+4j |

=COMPLEX(0,1) | Complex number with 0 and 1 as the real and imaginary coefficients | i |

=COMPLEX(1,0) | Complex number with 1 and 0 as the real and imaginary coefficients | 1 |