Reactance Calculator (Capacitive and Inductive)
Enter the frequency, capacitance and inductance.
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Capacitive reactance XC (Ω)
Capacitive reactance XC (Ω)
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Inductive reactance XL (Ω)
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Resonant frequency of L and C (Hz)
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Reactance Calculator (Capacitive and Inductive) by TheCalcTools
How the Reactance Calculator (Capacitive and Inductive) works
Capacitors oppose AC less as frequency rises: XC = 1 ÷ (2πfC). Inductors oppose it more: XL = 2πfL. Both are measured in ohms but shift the current’s phase by 90°.
Where XL equals XC, the circuit resonates at f = 1 ÷ (2π√(LC)), the basis of tuned circuits and filters.
The formula
XC = 1 ÷ (2πfC); XL = 2πfL; f₀ = 1 ÷ (2π√(LC))
Worked example
Using the default values shown in the calculator:
| Frequency (Hz) | 1000 |
|---|---|
| Capacitance (µF) | 1 |
| Inductance (mH) | 10 |
- At 1 kHz: 1 µF has XC = 159.155 Ω and 10 mH has XL = 62.832 Ω.
- They resonate at 1,591.55 Hz.
Result:
| Capacitive reactance XC (Ω) | 159.155 |
|---|---|
| Inductive reactance XL (Ω) | 62.832 |
| Resonant frequency of L and C (Hz) | 1,591.55 |
Frequently asked questions
Why does a capacitor block DC?
At 0 Hz its reactance is infinite, so no steady current flows once it has charged.
Sources and further reading
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.