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Math & statistics

Complex number arithmetic

Complex number arithmetic: Use componentwise addition/subtraction, (a+bi)(c+di)=(ac−bd)+(ad+bc)i, and multiply by the divisor’s conjugate for division.

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How it works

Use componentwise addition/subtraction, (a+bi)(c+di)=(ac−bd)+(ad+bc)i, and multiply by the divisor’s conjugate for division.

Input definitions

First real component
Enter the value in the labeled unit.
First imaginary component
Enter the value in the labeled unit.
Second real component
Enter the value in the labeled unit.
Second imaginary component
Enter the value in the labeled unit.
Operation
Choose Multiply / Add / Subtract / Divide.

A worked example

First real component
2
First imaginary component
3
Second real component
4
Second imaginary component
-1
Operation
Multiply
11 + 10i

Assumptions & limits

Finite numeric components, rounded to six decimal places in the formatted answer. No symbolic radicals or arbitrary precision.

Sources & review

Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.

Method updated 2026-10-17. Content checked against the stated method and examples. Our verification approach.

Common questions

Can I divide by a purely imaginary number?

Yes, provided its magnitude is nonzero and numerically representable. Division uses the complex conjugate so both real and imaginary parts are handled.

How does Complex number arithmetic work?

Use componentwise addition/subtraction, (a+bi)(c+di)=(ac−bd)+(ad+bc)i, and multiply by the divisor’s conjugate for division.

What are the limits of Complex number arithmetic?

Finite numeric components, rounded to six decimal places in the formatted answer. No symbolic radicals or arbitrary precision.

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