Capacitive Reactance Calculator

Capacitive reactance Xc is the opposition a capacitor offers to alternating current, measured in ohms. It is given by Xc = 1 / (2 pi f C), where f is frequency and C is capacitance.

Frequency sits in the denominator, so doubling the frequency halves the reactance. At high frequencies a capacitor behaves more like a short circuit, and at very low frequencies more like an open circuit.

About 159.15 ohms, from Xc = 1 / (2 pi * 1000 * 1e-6). This tool shows the full value as 159.1549 ohm.

Frequency accepts Hz, kHz or MHz, and capacitance accepts F, uF, nF or pF. The tool converts your entry to base hertz and farads before applying the formula.

The result is in ohms and auto-scales for readability: values at or above 1,000 ohms show as k ohm, and at or above a million as M ohm. Figures are rounded to four decimal places.

No. Both are measured in ohms, but reactance applies to alternating current and shifts the phase between voltage and current by 90 degrees, while resistance dissipates power and does not shift phase.

For an ideal capacitor the impedance magnitude equals the reactance. With a series resistance R, combine them as the square root of R squared plus Xc squared.

Yes. Capacitance also sits in the denominator, so a larger capacitor gives a lower reactance at a given frequency. Doubling either f or C halves Xc.

No. The formula runs entirely in your browser, so nothing you type is uploaded. It works offline once the page has loaded.