What is inductive reactance?

Inductive reactance (XL) is the opposition an inductor presents to alternating current. Unlike resistance, it depends on frequency — the higher the frequency, the greater the opposition. It is measured in ohms.

What is the formula for inductive reactance?

XL = 2πfL, where f is frequency in hertz and L is inductance in henries. Multiply 2π (≈ 6.2832) by frequency by inductance.

Does inductive reactance dissipate power?

No. A pure inductor stores energy in its magnetic field and returns it to the circuit. It causes a 90° phase shift between voltage and current but dissipates no real power.

How does inductive reactance differ from resistance?

Resistance is constant regardless of frequency and converts energy to heat. Inductive reactance is frequency-dependent and stores/returns energy without loss.

What happens to XL at DC (0 Hz)?

At DC the frequency is zero, so XL = 2π × 0 × L = 0 Ω. An ideal inductor is a short circuit at DC and only opposes changing (AC) current.

Can I use this for capacitive reactance?

No. Capacitive reactance uses a different formula (XC = 1 / 2πfC). Use the Capacitive Reactance Calculator for capacitors.

Inductive Reactance Calculator

Enter frequency and inductance to calculate inductive reactance (XL = 2πfL) in ohms.

Inputs

Frequency

Inductance

X_L = 2π × f × L

Result

Enter values and click Calculate

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Summary

Inductive reactance (XL) measures how much an inductor opposes AC current at a given frequency. It is calculated with XL = 2πfL, where f is frequency in hertz and L is inductance in henries. Higher frequency or greater inductance both increase the opposition to current flow.

How it works

Enter the AC signal frequency in hertz (or use the unit selector for kHz/MHz).
Enter the inductance value and choose the unit: H, mH, or µH.
The calculator applies XL = 2πfL and displays the result in ohms.
Phase angle is always +90° for a pure inductor — shown for reference.
Adjust either value and the result updates instantly.

Use cases

Designing RF filters and selecting the right inductor value.
Checking inductor behavior at mains frequency (50 Hz or 60 Hz).
Estimating impedance in audio crossover networks.
Verifying SPICE simulation results against hand calculations.
Teaching AC circuit theory in physics or electronics courses.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu