Decibel (dB) to Ratio Converter

Convert a decibel value into a ratio. Power ratio is 10^(dB/10) and amplitude ratio is 10^(dB/20).

Input

Convert a decibel (dB) value into a ratio. Both the power ratio and the amplitude ratio are calculated, and the selected type is shown as the main result.

Decibel value

Enter the dB value to convert. Negative values are allowed.

Type

Choose a power quantity or an amplitude quantity such as voltage or sound pressure.

Result

Power ratio (multiplier)

100x

Converted from 20 dB

Power ratio 10^(dB/10)

100 x

Amplitude ratio 10^(dB/20)

10 x

Power ratio = 10^(dB/10) and amplitude ratio = 10^(dB/20). The factor is 20 because power is proportional to the square of the amplitude.

How it works

A decibel (dB) expresses a ratio against a reference quantity on a logarithmic scale. The conversion differs depending on whether the quantity is a power quantity or an amplitude quantity such as voltage or sound pressure.
The power ratio is ratio = 10^(dB/10). For example, 3 dB is about 2 times and 10 dB is 10 times.
The amplitude (voltage) ratio is ratio = 10^(dB/20). The factor is 20 because power is proportional to the square of the amplitude.
0 dB equals a ratio of 1 (the same as the reference) for both types. A negative dB value represents a ratio smaller than 1, meaning attenuation.

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