Reactance & Impedance Calculator

Reactance & Impedance Calculator

Resistance (R)

Ω

Inductance (L)

H

Capacitance (C)

F

Frequency (f)

Hz

Impedance (Z)

Ω

Reactance and Impedance – Explanation

In alternating current (AC) circuits, opposition to current flow is not caused only by resistance. Components like inductors and capacitors also oppose current depending on frequency. This opposition is called reactance, and the total opposition is known as impedance.

Inductive Reactance (X_L) occurs in coils and inductors and increases with frequency:

X_L = 2πfL

Capacitive Reactance (X_C) occurs in capacitors and decreases with frequency:

X_C = 1 / (2πfC)

When resistance, inductance, and capacitance are present together, the total opposition is called impedance (Z), calculated using:

Z = √[ R² + (X_L − X_C)² ]

How to Use This Calculator

Enter known values for resistance, inductance, capacitance, and frequency. Leave the impedance field blank and click Calculate. The calculator will automatically compute reactance values internally and give the final impedance.

Example

Consider an AC circuit with:

• Resistance = 10 Ω
• Inductance = 0.05 H
• Capacitance = 100 µF (0.0001 F)
• Frequency = 50 Hz

X_L = 2π × 50 × 0.05 = 15.7 Ω
X_C = 1 / (2π × 50 × 0.0001) = 31.8 Ω

Z = √[10² + (15.7 − 31.8)²] ≈ 18.9 Ω

This calculator is extremely useful for EEE students, diploma learners, and engineers working with AC circuits, filters, transformers, and power systems. It saves time, avoids calculation errors, and helps visualize how frequency affects current flow in inductive and capacitive components.