Capacitive Reactance Calculator
The capacitive reactance calculator estimates the magnitude of opposition an ideal capacitor presents to sinusoidal alternating current at a given frequency.
How to use this calculator
- Enter frequency in hertz and capacitance in microfarads; both must be positive.
- Check the units and definitions before comparing results with another source.
- Change one input at a time when comparing scenarios, and keep the reporting period and assumptions consistent.
Formula used by the capacitive reactance calculator
Xc = 1/(2πfC)
- Xc = 1/(2πfC)
- This ideal formula excludes equivalent series resistance, leakage, component tolerance and frequency-dependent non-ideal effects.
- Inputs are checked for required values and valid ranges; displayed results are rounded for readability.
Worked examples
Worked example
A 10 µF capacitor at 1,000 Hz.
Xc = 1/(2π×1,000×10×10⁻⁶) ≈ 15.92 Ω.
Xc = 1/(2π×1,000×10×10⁻⁶) ≈ 15.92 Ω.
Understanding the result
The capacitive reactance calculator estimates the magnitude of opposition an ideal capacitor presents to sinusoidal alternating current at a given frequency.
This ideal formula excludes equivalent series resistance, leakage, component tolerance and frequency-dependent non-ideal effects.
Important notes
This ideal formula excludes equivalent series resistance, leakage, component tolerance and frequency-dependent non-ideal effects.
The result applies to the numbers and assumptions entered here; verify specifications for safety-critical or regulated uses.
Frequently asked questions
What happens to capacitive reactance as frequency increases?
For a fixed capacitance, it decreases as frequency rises.
Is reactance the same as resistance?
No. Reactance describes ideal energy-storing opposition in AC, while resistance dissipates energy; real components may include both.
How do I use this calculator?
Enter frequency in hertz and capacitance in microfarads; both must be positive.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.