Reactance Calculator


Determining the reactance XC by Selecting a capacitor C and frequency f is the most suitable. Capacitive reactance (symbolic representation XC) is actually a way of measuring a capacitor's resistance to AC (alternating current).

Just like resistance it is calculated in ohms, however reactance is somewhat more complicated compared to resistance due to the fact its value is dependent upon the frequency (f) of the electrical signal entering the capacitor and also on the capacitance, C.

Capacitive reactance, XC = 1 / (2 × π × f × C)

where: XC = reactance in ohms (ohm), f = frequency in hertz (Hz), C = capacitance in farads (F)The reactance XC is substantial for low frequencies and smaller at higher frequencies.

For constant DC which can be zero frequency, XC is incalculable (complete opposition), as per the standard rule that says capacitors transfer AC but block DC.As an example a 1 µF capacitor carries a reactance of 3.2 kΩ for any 50 Hz signal, however once the frequency is bigger at about 10 kHz its reactance is reduced to just 16 Ω.

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Capacitance C, frequency f, and capacitive reactance XC

Enter the values for capacitance and frequency, then press "calculate".

 Capacitance C and units 
Frequency fc and units 
Capacitive reactance XC 

Capacitor Conversion Table


1,000,000 pF = 1000 nF = 1 µF = 1 × 10−6 F
  100,000 pF = 100 nF = 0.1 µF = 1 × 10−7 F
    10,000 pF = 10 nF = 0.01 µF = 1 × 10−8 F
      1,000 pF = 1 nF = 0.001 µF = 1 × 10−9 F
        100 pF = 0.1 nF = 0.0001 µF = 1 × 10−10 F
          10 pF = 0.01 nF = 0.00001 µF = 1 × 10−11 F
            1 pF = 0.001 nF = 0.000001 µF = 1 × 10−12 F


SI multiples for hertz (Hz)
Value Symbol Name
103 Hz kHz kilohertz
106 Hz MHz megahertz
109 Hz GHz gigahertz
1012 Hz THz terahertz
Common prefixed units