Inductive Reactance Calculator

Inductive reactance Xl is the opposition an inductor presents to alternating current, measured in ohms. It comes from Xl = 2 pi f L, where f is frequency in hertz and L is inductance in henries.

Frequency multiplies inductance in the formula, so the faster the current alternates the harder the inductor pushes back. Double the frequency and the reactance doubles, which is why an inductor looks almost like an open circuit at very high frequencies.

About 62.8319 ohms. Putting f = 1000 Hz and L = 0.01 H into Xl = 2 pi f L gives 2 times pi times 1000 times 0.01, which the tool shows as 62.8319 ohm.

Frequency accepts Hz, kHz or MHz and inductance accepts H, mH or uH. The tool converts each to base SI units before calculating, so you can enter 1 kHz and 10 mH without doing any conversion yourself.

The reactance is rounded to four decimals, then shown in ohms below 1,000, kilo-ohms from 1,000 up, and mega-ohms from a million up. So 6283 ohms displays as 6.2832 k ohm.

Inductive reactance rises with frequency while capacitive reactance falls with it. In a series LC circuit the two are equal and cancel at the resonant frequency, leaving only resistance.

No, this tool reports ideal reactance only. A real coil also has winding resistance R, so its total impedance is the square root of R squared plus Xl squared, which is slightly larger than Xl alone.

At true DC the frequency is zero, so Xl is zero and an ideal inductor behaves as a plain wire. The calculator requires a positive frequency, so enter the AC frequency you actually care about.

No. The reactance is computed in your browser as you type, so the frequency and inductance you enter never leave your device.