Inductors pass DC easily but resist rapidly changing currents. Their reactance rises with frequency, which is why they are used in filters, chokes and switching power supplies.
How to use the Inductive Reactance Calculator
- Inductance L
- Frequency f
- Every result field is editable: type into Inductive reactance X_L and Frequency f plus every other field update to match.
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Enter the inductance and the frequency (or type a reactance into the result to find the frequency).
Inputs explained
| Field | What to enter |
|---|---|
| Inductance L | Units: mH, µH, nH, H |
| Frequency f | Units: Hz, kHz, MHz, GHz, THz, rpm |
What each result means
- Inductive reactance X_L = 2×pi×[Frequency f]×[Inductance L]
- Susceptance B_L = 1÷(2×pi×[Frequency f]×[Inductance L])
- Angular frequency ω = 2×pi×[Frequency f]
Example values
How the main result changes when Frequency f changes and everything else stays at the example values above:
| Frequency f (Hz) | Inductive reactance X_L (Ω) |
|---|---|
| 500 | 31.4159 |
| 750 | 47.1239 |
| 1,000 | 62.8319 |
| 1,250 | 78.5398 |
| 1,500 | 94.2478 |
| 2,000 | 125.6637 |
Formula
X_L = 2π·f·L = ω·L, B_L = 1/X_L
Worked example
Inputs — Inductance L: 10 mH; Frequency f: 1,000 Hz.
Results — Inductive reactance X_L = 62.83185 Ω; Susceptance B_L = 0.01592 S; Angular frequency ω = 6,283.18531 rad/s.
Key terms
- Susceptance
- Reciprocal of reactance.
Frequently asked questions
What is the reactance at DC?
Zero – an ideal inductor is a short circuit at DC.
Which way does the phase shift go?
Current lags voltage by 90°.
How is it different from resistance?
Reactance stores and returns energy instead of dissipating it.
What is a choke?
An inductor used to block high-frequency currents.