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Select a calculation
Choose reactance, inductance, stored energy, or RL time constant.
Circuit analysis workspace
Inductor Calculator
Calculate inductive reactance, unknown inductance, stored magnetic energy, and RL circuit time constant with automatic electrical unit conversion and clear formula tracing.
Live circuit math
Four calculation modes
Instant engineering results
Inductor Workbench
Select a calculation mode and enter the known circuit values.
AC circuit calculation
Inductive Reactance
Calculate the opposition an inductor presents to alternating current at a selected frequency.
XL = 2πfL
How it works
Analyze an Inductor in Four Steps
The calculator converts every entered value to its base SI unit, applies the selected formula, and displays the answer in a practical engineering unit.
02
Enter known values
Add the available component and circuit measurements.
03
Choose correct units
Mix H, mH, µH, Hz, kHz, amperes, and resistance units.
04
Review circuit output
See the primary result, converted values, and complete formula trace.
Inductor fundamentals
Understanding Inductors
An inductor is a passive electrical component that stores energy in a magnetic field when current flows through its winding. Inductance describes how strongly the component opposes a change in current.
In a steady DC circuit, an ideal inductor eventually acts like a short circuit. In an AC circuit, continuously changing current produces inductive reactance, which increases with both frequency and inductance.
Higher frequency increases reactance
Doubling the frequency doubles inductive
reactance when inductance stays unchanged.
Current cannot change instantly
The magnetic field creates a voltage that
opposes rapid changes in circuit current.
Real inductors are not ideal
Winding resistance, core loss, tolerance,
temperature, and saturation affect performance.
Inductor Formulas
Inductive reactance
XL = 2πfL
XL in ohms, f in hertz, and L in henries.
Unknown inductance
L = XL ÷ 2πf
Calculates inductance from reactance and frequency.
Stored magnetic energy
E = ½LI²
Energy is measured in joules and current in amperes.
RL time constant
τ = L ÷ R
Time constant is measured in seconds.
Practical uses
Where Inductor Calculations Are Useful
Inductor calculations are commonly used in power electronics, signal processing, filters, switching circuits, and electrical education.
Electronic Design
Select suitable inductors for filters, oscillators, and signal circuits.
Power Supplies
Estimate energy storage in buck, boost, and switching converters.
AC Circuit Analysis
Determine how strongly an inductor opposes current at a given frequency.
RL Timing Circuits
Analyze current rise and decay after switching a circuit on or off.
Repair and Testing
Compare measured reactance with expected component values.
Electrical Learning
Understand inductance, reactance, energy, and transient response.
Frequently asked questions
Inductor Calculator FAQs
Common questions about inductive reactance, stored energy, inductance units, and RL circuit behavior.
What does an inductor calculator calculate?
This calculator determines inductive reactance, unknown inductance, stored magnetic energy, and the time constant of a series RL circuit.
How do I calculate inductive reactance?
Multiply two times pi by frequency in hertz and inductance in henries. The result is inductive reactance in ohms.
Does inductive reactance increase with frequency?
Yes. Inductive reactance is directly proportional to frequency. A higher AC frequency creates greater opposition to current flow.
What is the difference between inductance and reactance?
Inductance is a component property measured in henries. Inductive reactance is the frequency-dependent opposition to alternating current and is measured in ohms.
How much energy does an inductor store?
Stored energy is one-half multiplied by inductance and the square of current. The result is expressed in joules.
What does an RL time constant mean?
The RL time constant indicates how quickly current rises or decays. After one time constant, rising current reaches about 63.2 percent of its final value.
Can I use millihenries and microhenries?
Yes. The calculator supports henries, millihenries, microhenries, and nanohenries and converts them automatically before calculating.
Are the calculated values exact for real inductors?
The calculator uses ideal formulas. Actual component behavior may vary because of tolerance, winding resistance, core losses, temperature, and saturation.
Electrical design reminder:
This calculator uses ideal component formulas. Real circuits can be
affected by component tolerance, winding resistance, parasitic
capacitance, core saturation, temperature, and manufacturer ratings.