Add sound levels correctly using logarithmic physics relationships. See combined intensity, source share, and equivalent power instantly. Clean inputs, quick exports, and results placed exactly above.
Enter independent sound sources in decibels. The tool converts each value to linear power, sums them, then converts back to decibels.
This worked example shows why decibel values cannot be added directly. Linear power must be summed first.
| Source | Level (dB) | Linear power ratio |
|---|---|---|
| Machine A | 70 | 10,000,000 |
| Machine B | 73 | 19,952,623 |
| Machine C | 68 | 6,309,573 |
| Total | 75.33 | 36,262,196 |
Independent sound levels must be converted from logarithmic form into linear power ratios before addition.
Linear conversion: Power ratio for each source = 10Li/10
Total power ratio: Sum = Σ 10Li/10
Combined sound level: Ltotal = 10 × log10(Σ 10Li/10)
Increase above loudest source: ΔL = Ltotal − Lmax
Equivalent identical-source count: N = 10ΔL/10
This method is appropriate for independent or incoherent sources, which is the standard case in noise assessment and environmental acoustics.
Decibels are logarithmic. A direct arithmetic sum ignores the underlying power ratios. Convert each value to linear power, add them, then convert back to decibels.
Two identical independent sources increase the total by about 3.01 dB. For example, 70 dB plus 70 dB becomes roughly 73.01 dB.
No. Coherent wave addition depends on phase relationships and pressure amplitudes. This calculator assumes independent sources, which is the common situation for practical noise analysis.
Yes. Negative decibel values are mathematically valid and represent levels below the chosen reference. The calculator accepts them as long as they remain within the allowed input range.
It shows each source’s share of the total linear power sum. A higher percentage means that source dominates the combined sound energy more strongly.
When one source is much louder, weaker sources contribute little linear power. The total then stays near the loudest level, with only a small increase.
It estimates how many equal-level sources would create the same increase above the loudest input. This helps interpret the total in practical planning terms.
Yes. Export the computed summary as CSV for spreadsheet work or create a PDF report from the result section for records, handoffs, or technical notes.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.