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IMSUB Function
Summary
The IMSUB function subtracts one complex number from another, returning the result in standard complex number format (x + yi). Perfect for engineering calculations, electrical engineering, and scientific applications requiring complex arithmetic.
Syntax
IMSUB(inumber1, inumber2)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| inumber1 | Complex Number |
Yes | The complex number from which to subtract (x+yi format) |
| inumber2 | Complex Number |
Yes | The complex number to subtract from inumber1 |
Using the IMSUB Function
IMSUB performs complex number subtraction following the formula (a+bi) - (c+di) = (a-c) + (b-d)i. Use COMPLEX function to create complex numbers from real/imaginary components, then IMSUB for subtraction operations in engineering formulas.
Common IMSUB Examples
Basic Complex Subtraction
=IMSUB("13+4i","5+3i")Subtracts 5+3i from 13+4i, returning 8+i
Engineering Example
=IMSUB(COMPLEX(10,5),COMPLEX(3,2))Subtracts 3+2i from 10+5i using COMPLEX function
Using j Notation
=IMSUB("7+9j","2+4j")Works with engineering j notation: returns 5+5j
Frequently Asked Questions
Common Errors and Solutions
#NUM! Error
Cause: Invalid complex number format
Solution: Use correct x+yi format with valid numbers
#VALUE! Error
Cause: Missing imaginary unit (i or j)
Solution: Include i or j: "3+4i" not "3+4"
Notes
- Use COMPLEX(real_num, i_num) to create complex numbers
- Supports both i (math) and j (engineering) notation
- Result always uses i notation
- Available since Excel 2007
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+