How to use the sound level at distance calculator
Estimate sound level at a new distance from a source. Enter level at reference distance, reference distance, new distance in the fields above; the level at new distance is computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- L1 — Level at reference distance (dB)
- r1 — Reference distance (m)
- r2 — New distance (m)
Worked example
With level at reference distance = 90 dB, reference distance = 1 m, new distance = 10 m, the calculator gives level at new distance ≈ 70 dB.
Frequently asked questions
What is the formula for the sound level at distance calculation?
Level at new distance (dB) = L1-20 × log10(r2 / r1). Here L1 is level at reference distance (dB), r1 is reference distance (m), r2 is new distance (m).
What inputs do I need for the sound level at distance calculator?
You need level at reference distance in dB, reference distance in m, new distance in m. 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.