How to use the adding decibels calculator
Combine two sound sources measured in decibels. Enter level 1, level 2 in the fields above; the combined level is computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- L1 — Level 1 (dB)
- L2 — Level 2 (dB)
Worked example
With level 1 = 70 dB, level 2 = 73 dB, the calculator gives combined level ≈ 74.76435 dB.
Frequently asked questions
What is the formula for the adding decibels calculation?
Combined level (dB) = 10 × log10(10^(L1 / 10)+10^(L2 / 10)). Here L1 is level 1 (dB), L2 is level 2 (dB).
What inputs do I need for the adding decibels calculator?
You need level 1 in dB, level 2 in dB. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.