Audio & acoustics

dB addition calculator

You enter several levels and the computer adds them together in a physically correct way using the linear power.

Updated on Apr 24, 2026 Calculator, calculation path and examples on one page

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Calculator

The overall level is formed logarithmically over the linear partial contributions.

Total level 84.02dB

The same levels do not add up linearly. For example, two identical sources only produce around +3 dB.

Examples

85dB plus 85dB.

Total level: 88.01dB

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85 dB, 85 dB and 80 dB together.

Total level: 88.65dB

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Four equal sources with 78 dB.

Total level: 84.02dB

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FAQ

Why can't I just add dB values?

dB are logarithmic. For correct addition, the values must first be converted into linear power.

How much do two equally loud sources bring?

Two identical levels add up to around +3 dB.

How much do four identical sources bring?

Four identical levels result in around +6 dB compared to a single source.

Can I use the computer for multiple speakers?

Yes, as long as you want to compare or summarize level values. You must assess directivity and geometry separately.

Are phase positions included?

No. The computer adds energetically and not via complex interference models.

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Calculate dB from the power or voltage ratio and calculate back vice versa.

Convert meters to delay time or milliseconds back to distance.

Convert frequency to wavelength or wavelength back to frequency.

Sources and notes

Formula: Ltot = 10 x log10(Sum of 10^(Li / 10))
Note: Energetic addition without phase model, room acoustics or directivity.