Capacitive Reactance
Calculator
Results
- Reactance (Ω)
- 318.309886
- Current (A)
- 0.722566
- Reactive power (VAr)
- 166.190251
Electrical results
| Reactance (Ω) | 318.309886 |
| Current (A) | 0.722566 |
| Reactive power (VAr) | 166.190251 |
formula-map diagram
- Reactance (Ω)
- 318.309886
- Current (A)
- 0.722566
- Reactive power (VAr)
- 166.190251
Electrical relationship
Formula
Xc = 1 / (2π × f × C)= 318.30988618379
Note
This is a simplified model: it applies the textbook relationship to the numbers you entered and assumes ideal components, steady-state sinusoidal conditions, balanced loads and copper resistivity of 0.0172 Ω·mm²/m at 20 °C. It ignores component tolerances, temperature drift, skin effect, harmonics, inrush, transformer and battery losses, and it is not a substitute for the wiring code that applies where you are. Have any installation sized and verified by a licensed electrician or engineer.
More in Electrical engineering
See all →Frequently asked questions
What is capacitive reactance and how is it calculated?+
Capacitive reactance Xc = 1 / (2*pi*f*C) measures the opposition a capacitor presents to AC current, expressed in ohms. Unlike resistance, it depends on frequency, not just the component's physical properties.
Why does reactance decrease as frequency increases?+
At higher frequencies, the capacitor's voltage doesn't have time to build up before the current reverses direction, so more current flows for the same voltage — meaning the capacitor 'blocks' less. That inverse relationship is why Xc drops as f rises.
What happens to capacitive reactance at DC (zero frequency)?+
At f = 0, the formula gives infinite reactance, matching the real-world behavior that a fully charged capacitor blocks DC current completely once its voltage matches the source.
Is capacitive reactance the same thing as resistance?+
No. Both are measured in ohms, but resistance dissipates energy as heat while reactance stores and releases energy without dissipating it (in an ideal capacitor), and it also introduces a 90-degree phase shift between voltage and current.
How do I use capacitive reactance to size a filter capacitor?+
Compare Xc at your frequency of interest to the other resistances in the circuit: choosing a capacitor whose Xc is much smaller than a load resistance at the frequencies you want to pass (or much larger at frequencies you want to block) is the basis of simple RC filter design.