Electrical · Free Calculator
Capacitive and Inductive Reactance Calculator
Calculate the AC opposition of a capacitor (Xc) or an inductor (XL) at any frequency, and the current it draws at a given voltage.
Xc = 1/(2πfC)XL = 2πfLAny frequencyCurrent at voltage
Hz
V
Capacitive reactance Xc318.31 Ω
Current at 230 V0.7226 A
Reactive power166.2 VAR
How this result was calculated
- Xc = 1 ÷ (2π × 50 × 1.000 × 10^−5 F) = 318.31 Ω
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Reactance Formulas
XC = 1 ÷ (2π × f × C)
XL = 2π × f × L
XL = 2π × f × L
Worked example
A 10 µF capacitor at 50 Hz: Xc = 1 ÷ (2π × 50 × 10 × 10⁻⁶) = 318.3 Ω, drawing 0.72 A at 230 V.
Key insight: capacitive reactance falls with frequency while inductive reactance rises. That is why capacitors pass high frequency noise to ground and chokes block it.
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Frequently Asked Questions
What is capacitive reactance?
The opposition a capacitor offers to alternating current, measured in ohms. It decreases as frequency or capacitance increases.
Why does a capacitor block DC?
At 0 Hz the reactance is infinite, so no steady current flows once the capacitor is charged.
Is reactance the same as resistance?
Both are in ohms, but reactance stores and returns energy instead of dissipating it, and causes a 90° phase shift.
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