SPL (Sound Pressure Level) Calculator

This tool calculates the SPL at a specified distance away from an amplifier speaker combination.


  • Speaker Sensitivity (usually specified in dB (1W/1m)
  • Amplifier Power (Watt)
  • Distance (meter or feet)




Speaker Sensitivity

It is a measure of how well power to a speaker is converted to sound energy.

As an example, the sensitivity of a speaker might be rated as 85 dB (1W/1m). This means that speaker produces a level of 85 dB at a distance of 1 meter, when driven with an amplifier that provides 1 Watt of power.

The higher the number in dB, the more sensitive the speaker and the more efficient it is in converting the power output of an amplifier to audio.

Amplifier Power

The output power of an amplifier is specified in Watt. It is important to review the specifications carefully and use the root-mean-square (RMS) power for this calculation. You might see the peak power advertised by some manufacturers as this is a larger (and more impressive) number. Don’t use the peak power for this calculation as it will provide an unrealistic estimate.


This is simply the distance away from the speaker (not the amplifier) where you want to find the SPL.

Example Calculation

Consider a 100 Watt amplifier that connects to a speaker with sensitivity of 85 dB (1W/1m).

The amplified SPL at 1 meter is 105 dB. (This makes sense when you consider that 100 Watt converts to 20 dB gain).

At a distance 20 meters away, the SPL is approximately 79 dB. The attenuation relative to the speaker sensitivity is around 6 dB.

Without the amplifier the loss would be 26 dB.

Related Calculators

  • Amplifier Speaker Matching – Find the amplifier gain (Watt) required to meet a target sound level at a specified distance from the speaker
  • Max SPL Calculator – explore the limits of your audio equipment
  • Add Sound Pressure Levels – this tool makes it easy
  • SPL Attenuation – A speaker’s data sheet usually specifies the SPL at 1 meter distance when the amplifier provides 1 Watt of power. This tool provides the formula and also calculates the attenuation at a specified distance away from the speaker.