Complex Number Calculator

Perform complex number arithmetic online with our free Complex Number Calculator. Add, subtract, multiply, divide, and find modulus, argument, and polar form instantly.

800.5K usesUpdated · 2026-04-26Runs locally · zero upload

How to Use Complex Number Calculator

The Complex Number Calculator lets you perform arithmetic on two complex numbers, z₁ and z₂, entirely in your browser. To use the Complex Number Calculator:

  1. Enter z₁ — type the real part (a₁) and imaginary part (b₁) for the first complex number.
  2. Enter z₂ — type the real part (a₂) and imaginary part (b₂) for the second complex number.
  3. Select an operation — choose Addition, Subtraction, Multiplication, or Division.
  4. The Complex Number Calculator instantly displays the result together with individual properties of each number (modulus, argument, conjugate, and polar form).

The Complex Number Calculator updates in real time — no button press required. This makes it easy to experiment with different values and operations.

Formula & Theory — Complex Number Calculator

The Complex Number Calculator implements the standard rules of complex arithmetic. A complex number is written as:

z = a + bi,  where i² = −1

| Operation | Formula | | -------------- | --------------------------------------------- | --- | ------------ | | Addition | (a₁ + b₁i) + (a₂ + b₂i) = (a₁+a₂) + (b₁+b₂)i | | Subtraction | (a₁ + b₁i) − (a₂ + b₂i) = (a₁−a₂) + (b₁−b₂)i | | Multiplication | (a₁+b₁i)(a₂+b₂i) = (a₁a₂−b₁b₂) + (a₁b₂+b₁a₂)i | | Division | z₁/z₂ = (z₁·z̄₂) / | z₂ | ² | | Modulus | | z | = √(a² + b²) | | Argument | arg(z) = atan2(b, a) | | Conjugate | z̄ = a − bi | | Polar form | z = r(cos θ + i sin θ) = re^(iθ) |

The Complex Number Calculator uses all of these formulas internally to produce accurate results for every supported operation.

Why the Polar Form Matters

The Complex Number Calculator displays the polar form r(cos θ + i sin θ) because it is particularly useful for multiplication and division. When multiplying, moduli multiply and arguments add; when dividing, moduli divide and arguments subtract.

Use Cases for Complex Number Calculator

The Complex Number Calculator is an essential tool in numerous STEM disciplines:

  • Electrical Engineering — Impedance analysis in AC circuits uses complex numbers extensively. The Complex Number Calculator helps engineers compute impedance addition and voltage phasor arithmetic quickly.
  • Signal Processing — Fourier transforms and filter design require complex number operations. The Complex Number Calculator simplifies coefficient calculations.
  • Physics — Quantum mechanics wave functions are expressed as complex amplitudes. The Complex Number Calculator assists with probability amplitude arithmetic.
  • Mathematics Education — Students learning complex numbers for the first time benefit from the Complex Number Calculator's step-by-step display of modulus, argument, and conjugate.
  • Control Systems — Stability analysis via the complex plane (Nyquist, root locus) involves complex arithmetic where the Complex Number Calculator provides quick verification.
  • Computer Graphics — 2D rotations can be expressed as complex number multiplications, making the Complex Number Calculator useful for graphics programming.

Whether you are analyzing circuits, studying for an exam, or verifying signal calculations, the Complex Number Calculator provides instant, accurate results with full transparency.

Frequently asked questions about Complex Number Calculator

What operations does the Complex Number Calculator support?

The Complex Number Calculator supports addition, subtraction, multiplication, and division of two complex numbers. It also computes the modulus, argument, conjugate, and polar form for each input.

How do I enter a complex number in the Complex Number Calculator?

Enter the real part and imaginary part separately. For example, to input 3 + 4i, set the real part to 3 and the imaginary part to 4. The Complex Number Calculator displays the combined form automatically.

What is the polar form shown by the Complex Number Calculator?

The Complex Number Calculator displays the polar form as r(cos θ + i sin θ), where r is the modulus (|z|) and θ is the argument in radians. This form is useful in electrical engineering and signal processing.

Can the Complex Number Calculator divide by zero?

No. If z₂ = 0 + 0i, the Complex Number Calculator shows an error message, since division by zero is undefined.

Is my data stored?

No. All calculations happen in your browser; nothing is sent to a server.