Reactance Calculator
Answer
Capacitors: Xc = 1 / (2π f C). Inductors: Xl = 2π f L. Reactance is in ohms for sinusoidal steady state with ideal L or C.
Calculator
How it works
Filters, coupling caps and choke selection all start with reactance at one frequency. This calculator returns Xc or Xl in ohms plus ω for the same f.
Pick capacitor or inductor, enter frequency in hertz and C in farads or L in henries. Warnings flag unit mistakes (tiny Xc often means microfarads typed as farads). Pair with the capacitor calculator when you also need an RC time constant.
Parameters used on this page
| Parameter | Value | Source |
|---|---|---|
| Capacitive reactance | Xc = 1 / (2π f C) | AC steady state |
| Inductive reactance | Xl = 2π f L | AC steady state |
| Angular frequency | ω = 2π f | Radians per second |
Worked example
1 µF at 1 kHz: Xc ≈ 159 Ω. 1 mH at the same frequency: Xl ≈ 6.28 Ω. At resonance you would match magnitudes — this tool does not compute resonance, only one element.
Pitfalls
- Using reactance at self-resonance of a cheap ceramic — ESL dominates long before the formula breaks.
- Confusing Xc with impedance when ESR is significant in a ripple calculation.
- Entering millihenries in the henry field without converting.
FAQ
What is the reactance of 10 µF at 60 Hz?
Xc ≈ 265 Ω.
How is this different from the capacitor calculator?
Same Xc formula; the capacitor page also computes RC τ. This page adds inductors.
Can I use kilohertz directly?
Enter frequency in hertz (1000 for 1 kHz) or convert with the unit converter.
Does this include resistance?
No. It is ideal reactance magnitude only.
Related
Sources
- Linear AC reactance for ideal L and C elements.