Capacitive Reactance Calculator
A 100 µF capacitor at 50 Hz has a capacitive reactance of 31.831 Ω, from X_C = 1/(2πfC).
31.8309886183791 Ω
Full answer, then cut to fewer decimals (not rounded):
- 31.8309886183791 Ω
- 31.830988618379 Ω
- 31.83098861837 Ω
- 31.8309886183 Ω
- 31.830988618 Ω
- 31.83098861 Ω
- 31.8309886 Ω
- 31.830988 Ω
- 31.83098 Ω
- 31.8309 Ω
- 31.830 Ω
- 31.83 Ω
- 31.8 Ω
- In mΩ
- 31830.98862 mΩ
- In kΩ
- 0.03183098862 kΩ
- In MΩ
- 0.00003183098862 MΩ
Step-by-step solution
- Convert units: C = 100 µF = 0.0001 F
- X_C = 1 ÷ (2π × f × C)
- X_C = 1 ÷ (2π × 50 × 0.0001)
- X_C = 31.83098862 Ω
Capacitive Reactance Formula
X_C = 1 / (2π f C)
X_C reactance (Ω), f frequency (Hz), C capacitance (F)
Worked Example
A 100 µF capacitor at 50 Hz:
- Convert units: C = 100 µF = 0.0001 F
- X_C = 1 ÷ (2π × f × C)
- X_C = 1 ÷ (2π × 50 × 0.0001)
- X_C = 31.83098862 Ω
In kΩ: 0.03183098862 kΩ · In MΩ: 0.00003183098862 MΩ
GATE tip
The cutoff of a first-order RC filter is where X_C = R: f_c = 1/(2πRC). Questions on filters and coupling networks reduce to this one equality.
More Electric Circuits Calculators
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RC & RL Time Constant Calculator
τ = RC, v_C(t) = V(1 − e^(−t/τ))
RL circuit: τ = L/R, i(t) = (V/R)(1 − e^(−t/τ)); discharging uses e^(−t/τ)
Example: A 10 kΩ resistor charging a 100 µF capacitor from 10 V, after 1 s: Time constant τ = 1 s.
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Impedance Calculator
Z = R + j(ωL − 1/ωC) (series)
parallel: 1/Z = 1/R + j(ωC − 1/ωL); ω = 2πf; φ = arctan(X/R)
Example: R = 10 Ω, L = 100 mH and C = 200 µF in series at 50 Hz: Impedance |Z| = 18.4462 Ω.
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Inductive Reactance Calculator
X_L = 2π f L
X_L reactance (Ω), f frequency (Hz), L inductance (H)
Example: A 100 mH inductor on 50 Hz mains: Inductive reactance X_L = 31.4159 Ω.
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RLC Resonance Calculator
f₀ = 1 / (2π√(LC)), Q = (1/R)√(L/C) (series)
parallel: Q = R√(C/L); bandwidth = f₀/Q; ζ = 1/(2Q)
Example: A series circuit with R = 10 Ω, L = 10 mH and C = 1 µF: Resonant frequency f₀ = 1591.55 Hz.
Frequently asked questions
Why does a capacitor block DC?
At f = 0 the reactance is infinite. As frequency rises, X_C falls, so capacitors pass high frequencies: the basis of coupling and decoupling capacitors.
How do I pick a coupling capacitor?
Make X_C small compared with the load at the lowest frequency: for a 10 kΩ load down to 20 Hz, X_C ≤ 1 kΩ needs C ≥ 8 µF.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
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APA
Scientific Converters. (2026, October 15). Capacitive Reactance Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/capacitive-reactance-calculator/
IEEE
Scientific Converters, "Capacitive Reactance Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/capacitive-reactance-calculator/