Enter the input voltage and the output voltage into the calculator to determine the decibel attenuation.

Attenuation Formula

The following formula is used to calculate the decibel attenuation.

dbv = 20* log(Vo / V in ) 
  • Where dbv is the attenuation in decibels
  • Vo is the output voltage
  • V in is the input voltage

To calculate the attenuation, take the log of the output voltage over the input voltage, then multiply by 20.

Attenuation Definition

Attenuation is defined as the reduction of power being supplied to a device caused by an attenuator.

Attenuation Example

How to calculate an attenuation?

  1. First, determine the output voltage.

    Measure the output voltage.

  2. Next, determine the input voltage.

    Measure the input voltage.

  3. Finally, calculate the attenuation.

    Calculate the attenuation using the formula above.


What is attenuation?

An attenuator is a two-port resistive network. It is used to reduce the power being supplied to a device. The attenuation is the size of this reduction in power expressed in decibels.

What is attenuation in decibels?

Attenuation is measure in decibels because attenuation is a unitless but very small number expressed in a logarithmic scale. Since decibels are also logarithmic and unitless, it helps analyze the small changes more easily.