IMSUB Function

All versions Engineering

The Excel IMSUB function subtracts one complex number from another — part of Excel’s complex-number toolkit for engineering and signal analysis.

Quick answer:

=IMSUB("3+4i","1+2i") // 2+2i

Syntax

=IMSUB(inumber1, inumber2)

Argument		Description
`inumber1`	Required	The first complex number.
`inumber2`	Required	The complex number to subtract.

How to use it

IMSUB subtracts one complex number from another. Complex numbers are written as text like "3+4i" (or with a "j" suffix). Build them with COMPLEX and pull the parts back out with IMREAL and IMAGINARY.

=IMSUB("3+4i","1+2i") // 2+2i

All IM functions take and return text. Keep complex numbers as text strings throughout your calculation chain; use IMREAL / IMAGINARY only when you need numeric parts for charts or further math.

Try it: interactive demo

Live demo

Enter a complex number (a+bi) and see the formula IMSUB would evaluate.

inumber

Practice workbook

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Frequently asked questions

How are complex numbers stored in Excel?

As text strings like "3+4i" or "3+4j". Build them with COMPLEX and read parts with IMREAL/IMAGINARY.

Does IMSUB return text or a number?

Text — a complex number string you can feed into other IM functions.

Can I mix i and j suffixes?

No — all complex numbers in one calculation must use the same suffix. COMPLEX lets you choose which.

What if my real or imaginary part is zero?

Excel simplifies the display: COMPLEX(3,0) returns "3" and COMPLEX(0,4) returns "4i".

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Related functions: COMPLEX · IMREAL · IMAGINARY · IMABS · IMSUM