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COMPLEX Function
Summary
The Excel COMPLEX function converts real and imaginary coefficients into a proper complex number representation in the form x + yi or x + yj, enabling mathematical operations with complex numbers in spreadsheets.
Syntax
COMPLEX(real_num, i_num, [suffix])Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| real_num | Number |
Yes | Real part of the complex number (required) |
| i_num | Number |
Yes | Imaginary part of the complex number (required) |
| suffix | Text |
No | Imaginary unit suffix: 'i' (default) or 'j' |
Using the COMPLEX Function
COMPLEX is the foundational function for working with complex numbers in Excel. It transforms separate real and imaginary components into a single complex number value that can be used with other complex math functions like IMABS, IMSUM, IMPRODUCT, etc.
Common COMPLEX Examples
Basic Complex Number Creation
=COMPLEX(3,4)Creates complex number 3+4i from real part 3 and imaginary part 4
Engineering Notation with 'j'
=COMPLEX(3,4,"j")Creates 3+4j using 'j' suffix common in electrical engineering
Pure Imaginary Number
=COMPLEX(0,1)Creates pure imaginary number i (0+1i)
Pure Real Number
=COMPLEX(1,0)Creates pure real number 1 (1+0i)
Frequently Asked Questions
Common Errors and Solutions
#VALUE! error
Cause: real_num or i_num is non-numeric
Solution: Ensure both coefficients are valid numbers
#VALUE! error
Cause: suffix is neither 'i' nor 'j'
Solution: Use only lowercase 'i' or 'j' for suffix
#VALUE! error
Cause: Uppercase 'I' or 'J' used
Solution: Use lowercase letters only for suffixes
Notes
- All complex functions require matching suffixes when using multiple complex numbers
- COMPLEX returns text formatted as complex number
- Available in Excel 2007 and later versions
- Use with functions like IMABS(), IMSUM(), IMPRODUCT()
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in: Excel 2003, Excel XP, Excel 2000, Excel 97
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+