Decibel Calculator
Find a power ratio in decibels as 10 × log10(value / reference).
Open toolAmplitude To Decibel Converter
Convert an amplitude ratio into decibels as 20 × log10(value / reference). Positive amplitudes in the same unit, with matched impedance when interpreting as a power ratio.
Free to useNo sign-upRuns in your browser
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Enter the inputs, then select Convert.
Your result
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Result will appear here
How Amplitude To Decibel Converter works
Convert an amplitude ratio into decibels as 20 × log10(value / reference).
Positive amplitudes in the same unit, with matched impedance when interpreting as a power ratio. Finite real inputs; output uses up to 12 significant digits. Floating-point results may be rounded.
How to use Amplitude To Decibel Converter
Follow the labelled inputs.
Enter amplitude value
Replace the example with amplitude value. The field labels specify the expected format and units.
Input and settings
Check the remaining inputs
Set reference amplitude. Positive amplitudes in the same unit, with matched impedance when interpreting as a power ratio.
Tool result
Run, review and save
Select Convert. Review the calculated result, then copy it or download the result text.
Review the details
Examples and uses for Amplitude To Decibel Converter
Check the supplied example
The starting example produces 20 dB. Convert an amplitude ratio into decibels as 20 × log10(value / reference).
Use your own inputs
Read the labels for amplitude value and reference amplitude. Positive amplitudes in the same unit, with matched impedance when interpreting as a power ratio.
Record a reviewed result
Copy the calculated result into your notes. Keep the formula and assumptions with it if someone else needs to reproduce the calculation.
How to read the result
Read the units and assumptions with the output.
Convert an amplitude ratio into decibels as 20 × log10(value / reference).
Positive amplitudes in the same unit, with matched impedance when interpreting as a power ratio. Finite real inputs; output uses up to 12 significant digits. Floating-point results may be rounded.
Supported input and limits
Check the stated scope before you run it.
Positive amplitudes in the same unit, with matched impedance when interpreting as a power ratio. Finite real inputs; output uses up to 12 significant digits. Floating-point results may be rounded.
The input stays in this browser. Copy result and Download save the same displayed text.
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Open toolAmplitude To Decibel Converter: common questions
Answers about using Amplitude To Decibel Converter and understanding its results.
What assumptions and input limits apply?
Positive amplitudes in the same unit, with matched impedance when interpreting as a power ratio. Finite real inputs; output uses up to 12 significant digits. Floating-point results may be rounded.
How can I save the output?
Use Copy result to copy the displayed text, or Download to save it as a text file. The tool runs in your browser and does not require an account.
Convert with your input
Check the calculated result, then copy or download it.