Calculate ideal inductive reactance in ohms from henrys and AC frequency, reverse-solve inductance or frequency, and compare admittance magnitude, ideal inductor RMS current and frequency effects.

Henrys and ohms measure different quantities. This uses ideal sinusoidal AC inductive reactance at the specified frequency.

Circuit context and frequency comparison

Blank omits current. Zero means zero applied AC voltage.

Default: twice the frequency, with the same inductance.

Reactance Formula

The following formula is used to calculate the reactance in ohms from inductance in henry and frequency in hertz.

XL = 2 × π × f × L

Variables:

  • X_L is the reactance (ohms)
  • f is the frequency (hertz)
  • L is the inductance (henry)

To calculate ideal inductive reactance, multiply 2 times π times the frequency in hertz times inductance in henrys. The inverse formulas are L = X_L / (2πf) and f = X_L / (2πL). For an ideal inductor Z = jX_L and Y = −j/X_L; the positive value 1/X_L is admittance magnitude. RMS current is V_RMS / X_L only when that RMS voltage is across the ideal inductor. Real winding resistance and parasitic effects are outside this model.

Henry to Ohms Conversion Table (Inductive Reactance, f = 1 kHz)
Inductance (H) Reactance (Ω)
0.0016.283
0.00159.425
0.002213.823
0.003320.735
0.004729.531
0.006842.726
0.01062.832
0.01594.248
0.022138.230
0.033207.345
0.047295.310
0.068427.257
0.100628.319
0.150942.478
0.2201382.301
0.3302073.451
0.4702953.097
0.6804272.566
1.0006283.185
2.00012566.371
* Rounded to 3 decimals. Assumes sinusoidal AC at f = 1 kHz. Formula: XL = 2π f L. At 1 kHz: 1 H ≈ 6283.185 Ω.

What is Reactance?

Reactance is a measure of the opposition that a circuit presents to the flow of alternating current (AC) due to its inductance or capacitance. Inductive reactance, which is caused by inductors in a circuit, increases with frequency and inductance. It is an important factor in the design and analysis of AC circuits, particularly in the context of impedance, filters, and resonance.

How to Calculate Reactance?

The following steps outline how to calculate the Reactance.

  1. First, determine the frequency (f) in hertz.
  2. Next, determine the inductance (L) in henry.
  3. Next, gather the formula from above = X_L = 2 * π * f * L.
  4. Finally, calculate the Reactance (X_L) in ohms.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

frequency (f) = 60 hertz

inductance (L) = 0.1 henry. At 60 Hz, X_L = 2π × 60 × 0.1 ≈ 37.699112 Ω.