Headphone Power Calculator — Voltage, Current & Amplifier Limits

Convert headphone sensitivity into required voltage, current and power. Compare headphones and explicit amplifier voltage and current limits.

Turn a headphone specification into the voltage, current and power it needs. Compare several headphones using the same target level, then check an amplifier’s entered electrical limits.

Your headphone comparison

These are editable arithmetic examples, not brand specifications or recommended listening levels.

Example specifications

The reference uses 100 Ω and 100 dB SPL at 1 mW, target 100 dB SPL, no reserve or amplifier. The voltage-reference example uses 300 Ω and 104 dB SPL at 1 V RMS, target 100 dB SPL and no reserve or amplifier: 0.63096 V RMS and 2.1032 mA RMS. The current comparison uses 100 Ω at 100 dB SPL/mW and 25 Ω at 110 dB SPL/V; target 110 dB SPL, no reserve, 2 V RMS open circuit, 0 Ω source resistance and a 20 mA RMS current limit. Both need 1 V RMS; the second exceeds the entered current limit.

Target sound pressure level · dB SPLCalculation target at the specification’s test frequency; not measured playback volume.

Extra electrical headroom · dBAdded to the target. Enter your own reserve; no universal value is assumed.

Target level: 100 dB SPL

Explore the electrical demand with the slider or arrow keys. This does not play sound or control your device.

Compare with an amplifier envelope

Enter an explicit nominal source model. A single wattage rating at a different load does not determine these limits. Open-circuit voltage is the source before its output resistance; a voltage measured under load is a different quantity.

Use the entered amplifier envelope

Electrical demand at 100 dB SPL

Target 100 dB SPL + 0 dB extra electrical headroom. Nominal resistive load, per channel.

1 mW reference

Power per channel1 mW

Voltage at headphone0.31623 V RMS

Current per channel3.1623 mA RMS

Equivalent sensitivity: 100 dB SPL at 1 mW · 110 dB SPL at 1 V RMS.

Headphone shown in the diagramResults above include every comparison.

The estimate uses nominal impedance and the stated sensitivity. It does not measure playback SPL, determine hearing safety, predict distortion or guarantee amplifier compatibility. Impedance and output limits can vary with frequency and load.

Complete comparison record

1 mW reference: 100 Ω, sensitivity 100 dB SPL at 1 mW. At target 100 dB SPL: 1 mW per channel, 0.31623 V RMS, 3.1623 mA RMS. No amplifier envelope entered.

Formula, units and limits

At nominal resistance R, power P = V²/R and current I = V/R. If sensitivity is S mW in dB SPL at 1 mW, voltage sensitivity S V = S mW + 10 log₁₀(1000/R). Required headphone voltage = 10^((target + reserve − S V)/20). Power in mW = 1000 V²/R; current in mA = 1000 V/R. Increasing the target by 10 dB multiplies power by ten.

The source envelope assumes a nominal resistive load and output resistance R out. The voltage-only ceiling at the headphone is V open × R/(R + R out). With a known current limit I max in amperes, the second ceiling is I max × R; the model uses the lower voltage. With an unknown current limit, only a voltage ceiling can be calculated, and overall compliance remains unknown. A zero source or zero current limit has no output; it has no finite SPL ceiling.

Use passive headphones with a compatible specification. This tool does not model active or electrostatic headphones, music crest factors, EQ, frequency response, noise, headphone power handling, volume knobs or exposure duration. All voltage and current values here are RMS quantities; do not enter peak values as RMS. Supported inputs: nominal impedance 0.1–10,000 Ω; sensitivity 0–160 dB SPL; target 0–140 dB SPL; reserve 0–40 dB, with a combined maximum of 160 dB. These are calculation bounds, not listening recommendations. Compare up to 12 headphones.

Audeze: sensitivity, impedance and amplifier power · Audient: voltage, current and source resistance.