Inductive Reactance Calculator — X_L = 2πfL
Find the inductive reactance (X_L) of an inductor in an AC circuit. Reactance is the opposition an inductor offers to alternating current — it grows linearly with both frequency and inductance.
Hz
H
Opposition to AC current by the inductor
- 1
Angular frequency
2π × 60 = 376.9911ω = 2πf (rad/s) - 2
Inductive reactance
376.9911 × 0.1 = 37.6991
How does this calculator work?
Inductive reactance X_L = 2π × f × L (ohms) is the opposition an inductor applies to alternating current. It grows linearly with frequency (Hz) and inductance (H) and is zero at DC. Enter frequency and inductance to get X_L in ohms instantly.
Formula
How this is calculated
When alternating current flows through an inductor, the continuously changing current creates a changing magnetic field that induces a back-EMF opposing the current change. This opposition is called inductive reactance X_L, measured in ohms. Unlike resistance it does not dissipate power as heat — the inductor stores energy in its magnetic field each half-cycle and returns it during the next.
The formula X_L = 2π × f × L shows reactance scales linearly with frequency f (Hz) and inductance L (henries). Angular frequency ω = 2πf is a useful intermediate quantity. At DC (f = 0), reactance is zero — an ideal inductor is a short circuit for DC. As frequency rises, reactance grows proportionally, which is why inductors act as "chokes" to block high-frequency signals while passing DC.
This formula covers ideal inductors only. Real inductors also have DC winding resistance (DCR) and parasitic capacitance that becomes significant at high frequencies, causing self-resonance. For the full impedance of an RL series circuit, combine using Z = √(R² + X_L²). Inductive reactance depends only on frequency and inductance, not on current magnitude.
Frequently asked questions
Higher frequency means the current reverses direction faster, inducing a larger back-EMF at each instant and therefore greater opposition to the current. At DC (zero frequency) there is no changing current and no back-EMF, so reactance is exactly zero. Doubling frequency exactly doubles X_L.
Resistance converts electrical energy to heat irreversibly. Inductive reactance opposes current without dissipating power — energy is stored in the magnetic field and returned each cycle, producing a 90° phase shift between voltage and current. In a circuit they combine as Z = √(R² + X_L²).
X_L = 2π × 50 × 0.1 ≈ 31.4 Ω. At 60 Hz the same coil gives ≈ 37.7 Ω. Reactance scales exactly with frequency — doubling the frequency doubles X_L for a given inductor.
Also known as
TG we-Calculate Editorial Team. (2026). Inductive Reactance Calculator — X_L = 2πfL [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/inductive-reactance-calculator
TG we-Calculate Editorial Team. "Inductive Reactance Calculator — X_L = 2πfL." TG we-Calculate. 2026. https://we-calculate.com/calculator/inductive-reactance-calculator.
TG we-Calculate Editorial Team, "Inductive Reactance Calculator — X_L = 2πfL," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/inductive-reactance-calculator
@misc{wecalculate_inductive_reactance_calculator, title = {Inductive Reactance Calculator — X_L = 2πfL}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/inductive-reactance-calculator}}, year = {2026}, note = {TG we-Calculate} }
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