Decibel Calculator
Add sound levels in decibels, find the difference between two levels as a ratio, and convert between dB and power or amplitude ratios.
How to use
- 1To add sources, list their dB levels separated by commas.
- 2To compare, enter two levels to see the power and loudness difference.
How it's calculated
Combined level = 10 log₁₀(Σ 10^(Lᵢ/10)). Power ratio = 10^(ΔdB/10); amplitude (pressure) ratio = 10^(ΔdB/20). +10 dB sounds roughly twice as loud.
Frequently asked questions
Is 60 dB + 60 dB = 120 dB?
No — two equal sources add 3 dB, so 60 + 60 dB = 63 dB.
How much louder is +10 dB?
10× the sound power, and perceived as roughly twice as loud.
What levels damage hearing?
Prolonged exposure above about 85 dBA can cause hearing loss; above 120 dB can cause immediate damage.