Headphone Amplifier Power Calculator

Enter your headphone's impedance and sensitivity. The calculator tells you how much power your amp needs and whether a typical portable or desktop amp will drive them properly.

How to read the results

The power figure is what your amplifier must deliver at the jack to hit your target peak level. Judge it together with the voltage figure, because most headphones that "need an amp" are voltage-limited, not power-limited: a decent dongle manages roughly 100 mW and 2 Vrms, a real desktop amp several times that. The difficulty rating on the right compares your headphones against those two limits at once.

This is why a 600Ω Beyerdynamic can run happily from a dongle at sane listening levels and still be called "hard to drive" on forums — the forum is quoting numbers for ear-splitting peak levels almost nobody actually uses.

About the numbers in the dropdown

Every figure in the headphone list is stored as dB per milliwatt, because that is what this calculation needs. That sounds like a detail. It is the single most common reason online headphone calculators give wrong answers.

Manufacturers split roughly into two camps. Beyerdynamic, Grado and most Japanese brands quote dB/mW. Sennheiser, AKG, Focal and nearly every Chinese IEM maker quote dB per volt — SPL measured at 1 Vrms instead. The two are not interchangeable, and the gap between them grows as impedance drops. Convert with:

dB/mW = dB/V − 10 × log₁₀(1000 / Z)

Worked example: AKG quotes the K702 at 105 dB and 62Ω. Read as dB/mW, that makes it look easy to drive. It is actually 105 dB per volt, which works out to about 93 dB/mW — roughly 12 dB less sensitive than the spec sheet appears to say, and exactly why the K701/K702 family has a reputation for needing a real amp despite a modest 62Ω rating.

The list here was rebuilt with that conversion applied throughout. Where a figure could not be pinned to a manufacturer sheet or a trustworthy measurement, an approximation from the closest documented variant was used. Anything published as a nominal spec — by anyone, including the manufacturer — is a starting point, not a measurement of the pair on your head: production tolerance alone runs a few dB. Treat the output as a sizing guide, not a verdict.

Voltage swing matters as much as power. High-impedance headphones are current-efficient but voltage-hungry — they need an amplifier with a high voltage rail, which is why many dedicated headphone amps run from ±15V or higher power supplies.

The same arithmetic, run across every headphone here

A calculator answers one pairing at a time. Run the identical formula over all 567 dynamic and planar models in this database — the 11 electrostatics are excluded, because an energiser is a different machine — and the shape of the answer stops being a matter of opinion.

At a 100 dB SPL peak, the median headphone here needs 1.0 mW and 0.16 V. Not 100 mW. One milliwatt, and about a sixth of a volt. 279 of the 567 models need less than a milliwatt; 181 need less than 100 mV. Exactly one model needs more than 100 mW, and 8 need more than one volt.

None needs more than two volts. That is the number worth sitting with. Two volts and a hundred milliwatts is roughly what a competent USB-C dongle delivers, and on this evidence it is not a floor to clear so much as a ceiling almost nothing reaches. Sorted by how far they fall short of that dongle, 489 of the 567 models come out easy, 71 moderate and 7 demanding.

Which half of the dongle runs out first is the more useful question, and the answer is lopsided: for 558 of the 567 models the voltage rail is the binding limit, and for only 9 is it the power. “Needs more power” is, nine hundred and ninety-nine times in a thousand, a sentence about volts. The most voltage-hungry headphone in the whole database is the HiFiMAN Susvara at 60 Ω, and it asks for 1.73 V and 50 mW. The most power-hungry is the Symphonium Titan at 3 Ω: 105 mW, but only 0.56 V.

Worked out for the models people actually look up

These are the numbers the calculator above produces, for a 100 dB peak, written out. The last column counts how many of the 280 sources catalogued on this site reach that level on that headphone with any headroom at all — not how many sound good on it, just how many are not out of road.

Read down the voltage column rather than the power column. The Sennheiser HD 600 wants 1.41 V from 6.61 mW; the in-ears near the bottom want a few tens of millivolts from a few thousandths of a milliwatt. Across the fourteen rows the power figures span a factor of 794 and the voltages a factor of 55 — the same headphones and the same arithmetic, with the power column spreading 15 times as far as the voltage one. That is the whole reason a dongle surprises people.

Doing it without the calculator

Three steps, and the only input you need from the spec sheet is impedance and sensitivity — in dB/mW. Taking the Sennheiser HD 600: 300 Ω and 91.8 dB/mW.

1. Power. Every 10 dB costs ten times the power, so the power for any target level is 10^{(target − sensitivity) / 10} milliwatts. For a 100 dB peak: 10^{(100 − 91.8)/10} = 6.61 mW.
2. Voltage. V = √(P × Z) with power in watts: √(6.61 / 1000 × 300) = 1.41 V.
3. Current. I = V / Z = 4.7 mA. Almost never the limit, and the reason the 600 Ω version of a headphone is usually the easier one to drive from a weak source, not the harder one.

If the sheet gives dB/V instead — and most of the industry does — convert first with dB/mW = dB/V − 10 log₁₀(1000 / Z). The Sennheiser HD 600 at 91.8 dB/mW is 97.0 dB/V; skip the conversion and you will size an amplifier for a headphone you do not own. 261 of the 280 sources here clear it.