Sound Level Calculator
Combine decibels and distance loss.
Enter your values
ⓘ Live results
Results
- Combined level
- 79.5 dB
- Level at distance
- 61.4 dB
- Loss over distance
- 18.1 dB
- Hearing risk
- Below action level
Quick answer
Decibels add logarithmically — two equal sources give only a 3 dB increase.
L = 10 log10(Σ10^(Li/10))
How to use the Sound Level Calculator
- 1Enter each source level in decibels.
- 2Enter the distance and reference distance.
- 3Check against the 85 dB action level.
Worked example
Using the values the calculator loads with:
Inputs
- Source 178 dB
- Source 274 dB
- Source 30 dB
- Distance from source8 m
- Reference distance1 m
Results
- Combined level79.5 dB
- Level at distance61.4 dB
- Loss over distance18.1 dB
- Hearing riskBelow action level
Frequently asked questions
Why don't decibels add normally?
The scale is logarithmic — doubling power adds only 3 dB.
How much does distance help?
Each doubling of distance drops free-field level by 6 dB.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.