Inductive Reactance Calculator

Formula used on this page

For this worksheet, the governing relationship is XL = 2πfL; I = V ÷ XL. The participating entries are Frequency, Inductance, and Applied RMS voltage.

With the current entries, the primary answer is 37.70 Ω. Preserve the raw inputs when replacing this example.

Calculate inductive reactance and ideal RMS current at a selected voltage. Capacitive Reactance Calculator may be useful for the next related quantity.

Input notes

Record frequency, waveform, phase arrangement, and whether voltage is line or phase. Write down whether each entry is measured, rated, assumed, or calculated.

A denominator entry cannot be zero. Confirm decimal placement whenever a source uses a different unit scale.

Frequency

Default example: 60 Hz. Enter frequency in Hz.

Inductance

Default example: 0.1 H. Enter inductance in H.

Applied RMS voltage

Default example: 120 V. Enter applied RMS voltage in V.

Checks that catch bad inputs

An unlabeled assumption can make an otherwise correct result unusable.

Compare the magnitude with a quick independent estimate.

Where this estimate can fail

Winding resistance, core loss, and saturation are not included.

The arithmetic intentionally leaves out frequency-dependent loss, parasitics, and waveform distortion. Use measurements, manufacturer data, or another calculation for effects that can change the decision.

Use RMS values unless an input explicitly requests peak amplitude.

Sensitivity check

Change Frequency from 60 Hz to 72 Hz without altering the remaining fields. The calculated value shifts from 37.70 Ω to 45.24 Ω.

Keep both cases when the changed input represents genuine uncertainty.

Using this result in a larger analysis

Review inductance and the remaining entries as one case. If one value belongs to another temperature, load, or time period, separate the scenarios.

After calculating inductive reactance, compare its magnitude with impedance, phase, waveform, and equipment ratings. An independent order-of-magnitude check can reveal a misplaced decimal or unit prefix.

Document any effect handled outside this page, especially startup transients, resonance, and measurement bandwidth. That note prevents a later reader from assuming the simple equation covered it.

Conditions that deserve another case

The calculator rejects values outside its stated field limits, but a numerically valid entry can still describe the wrong condition. Confirm frequency, inductance, and applied RMS voltage against the original source before saving the result.

Use an additional case for startup transients, resonance, and measurement bandwidth when that behavior is not negligible. Keep the baseline intact so the effect of each changed assumption remains visible.

Questions from practical use