Air Core Coil Inductance Calculator

The coil is the most recognizable form of an inductor. An air core inductor is a unique type of inductor that achieves its specific inductance value without relying on a ferromagnetic material.

An interesting advantage of an air core coil is its immunity to changes in inductance due to current flow, which sets it apart from coils using ferromagnetic materials. Air coils find great utility in audio crossover filters for hi-fi speakers, where avoiding disturbance is crucial, and in radio transmitters to prevent harmonic production. There are several applications, where you can choose an air core coil not solely for its inductance value but for its role as a proximity sensor, loop antenna, induction heater or tesla coil

On the downside, the absence of a high permeability core means that more turns and/or larger coils are required to achieve similar same inductance as a ferrous core coil. This coil also results in larger coils, lower self-resonance due to higher interwinding capacitance, and higher copper loss.

This online electrical calculator helps you calculate the inductance of an air core inductor coil. Simply input the diameter, length, and number of turns of the coil to obtain the desired result. It enables you to quickly determine the inductance value based on the provided parameters.

Coil Diameter
Coil Length
Number of turns


\[Inductance = \frac {(d^2 * n ^ 2)}{18d + 40l}\]

where :

  • d = Coil Diameter,
  • l = Coil Length,
  • n = Number of turns.

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