Headphone Power Calculator
Estimate the power, voltage, and current needed to drive headphones.
Use headphone sensitivity, target loudness, and impedance to size your amplifier.
Result
--
Run the calculation to see the headphone power estimate.
| Metric | Value |
|---|---|
| Required power | -- |
| Required voltage | -- |
| Required current | -- |
| Safe amp impedance | -- |
Quick Answer
Use the headphone sensitivity and target loudness to estimate the required power, then convert that power into voltage and current using the headphone impedance.
How to Calculate
- Enter the target loudness in dB SPL.
- Choose whether sensitivity is given in dB per mW or dB per V.
- Enter sensitivity, headphone impedance, and amplifier output impedance.
- Click Calculate.
Formula
dB / mW: power(mW) = 10(target - sensitivity) / 10
dB / V: voltage(V) = 10(target - sensitivity) / 20
Current = voltage / impedance
Worked Examples
Example 1: 100 dB SPL, 95 dB/mW, and 32 ohms needs about 3.16 mW.
Example 2: 100 dB SPL, 100 dB/V, and 32 ohms needs about 1.00 V.
Example 3: A 32 ohm headphone should ideally be paired with an amp impedance below 4 ohms.
How to Interpret Your Results
| Output | Meaning | Action |
|---|---|---|
| Required power | The drive power needed for the target loudness. | Compare it with the amplifier output. |
| Required voltage | The approximate voltage swing needed. | Check that the amplifier can reach it. |
| Safe amp impedance | One eighth of the headphone impedance. | Keep the amp output impedance below this value. |
Frequently Asked Questions
Use the type provided by the headphone manufacturer. If both are listed, choose the one that matches your spec sheet.
A lower amplifier output impedance helps preserve frequency response and sound quality.
Yes. Just make sure the sensitivity and impedance values are correct for the specific model.
Related Calculators
References
- OmniCalculator reference page
- The 1/8 impedance rule is a common rule of thumb for amp matching.
- Last reviewed: March 2026.