Audio Amplifier Output Calculator

Use this tool to calculate the amplifier output power for an audio system consisting of an amplifier, speaker or subwoofer.

How to use the calculator

  • Enter
    • Amplifier RMS output power per channel
    • Amplifier impedance in ohm (Ω)
    • Impedance in ohm (Ω) for each speaker or subwoofer connected to the amp
  • The tool will provide RMS output power from the amp


Example Calculation

Let’s use this amplifier from DS18 as an example. It has an RMS power rating of 200 W per channel at an impedance of 4 ohm.

DS18 SXE-3000.4D/RD Car Amplifier Stereo Full-Range Class D 4-Channel 200x4 RMS @4 OHM 3000 Watts - Powerful and Compact Amp for Speakers in Car Audio System

If we want to match them with these JBL Speakers, with 60 W nominal power and 2.3 Ω impedance, there’s a risk that these speakers will be damaged if they are over driven. According to the calculator on this page, the amplifier will deliver 348 W of power to the speaker.

On the other hand, let’s consider speakers with 250 W RMS and 4 Ω impedance.

In this case, the amplifier will be able to deliver 200 W RMS with the impedance match. This is a reasonably compatible solution.

Ideally, based on this speaker/amplifier matching calculator, the amplifier wattage should be between 225 and 300 Watt. When the amp power is lower than that (200 W in this case), there’s a chance that clipping will occur and result in speaker damage.

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