Headphone Power Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

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The Headphone Power Calculator answers a narrow everyday question without hiding the arithmetic. It is built to calculate electrical power delivered to headphones from RMS voltage and impedance, with an SPL estimate when sensitivity is expressed in dB/mW. For the Headphone Power Calculator, that makes the result easy to sanity-check because you can change one assumption and see immediately what moved.

What this calculator does

The primary result is “Electrical headphone power” and is displayed in mW. Supporting values on the page include Power, Estimated SPL from sensitivity. In practical terms, the Headphone Power Calculator is meant to calculate electrical power delivered to headphones from RMS voltage and impedance, with an SPL estimate when sensitivity is expressed in dB/mW. The Headphone Power Calculator does not infer or add inputs that are absent from its visible form.

How to use it

Enter RMS voltage, Headphone impedance and Sensitivity. For the Headphone Power Calculator, check the selected unit beside every measured quantity. When comparing Headphone Power Calculator scenarios, change one field at a time so the source of the difference stays obvious.

How the calculation works

For the Headphone Power Calculator, electrical power is P = V²/R. The page converts watts to milliwatts, then estimates sound-pressure level as sensitivity + 10×log10(power in mW). That SPL step assumes the entered sensitivity uses dB per mW.

Example

With 1 V RMS into 32 Ω, P = 1²/32 = 0.03125 W = 31.25 mW. With sensitivity set to 100 dB/mW, the page estimates about 114.9 dB using its sensitivity formula.

How to interpret the result

Use the milliwatt result to compare the electrical demand of a headphone/load scenario. The estimated SPL can be a rough sensitivity cross-check only when the sensitivity unit matches the formula; it should not be treated as a measured level at your ear.

Limitations and notes

For the Headphone Power Calculator, the acoustic estimate is only valid when sensitivity is truly specified in dB/mW; some headphones publish dB/V instead. Amplifier clipping, frequency response, seal, measurement method, and listening duration are not modeled, so the SPL number is not a safe-listening prescription.