Inductor Calculator
Calculate the energy stored in an inductor or its inductive reactance at any frequency.
How it works
- 1Choose a mode — stored energy or reactance.
- 2Enter the inductance in millihenries (mH) plus the current or frequency for that mode.
- 3The calculator applies E = ½LI² or Xl = 2πfL and shows the result.
Use cases
- Designing power-supply filter chokes and checking their stored energy.
- Estimating a coil’s impedance at mains frequency (50 or 60 Hz).
- Comparing two inductors by energy storage or reactance.
Frequently asked questions
What is inductive reactance?
Xl = 2πfL is the opposition an inductor presents to AC. Unlike resistance it stores and returns energy, and it rises with frequency — a 100 mH coil is ≈ 31.4 Ω at 50 Hz.
How is the stored energy calculated?
The energy in an inductor’s magnetic field is E = ½LI². A 100 mH inductor carrying 2 A stores 0.5 × 0.1 × 4 = 0.2 J.
Why enter inductance in millihenries?
Practical chokes and coils are usually rated in mH or µH, so mH avoids tiny decimals; the tool converts mH × 10⁻³ to henries.
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