Find the level difference 10 log₁₀(P₂ / P₁) between two powers or intensities.
| Level (dB) | – |
Use this calculator for a power or intensity ratio in decibels. The formula is 10 log₁₀(P₂ / P₁). A factor of 10 in power is +10 dB; a factor of 2 is about +3 dB; equal values give 0 dB. Sound pressure levels often use 20 log₁₀ of a pressure ratio instead; here the formula is the power/intensity form.
P₁ = 1 and P₂ = 2 give about +3.01 dB. Both values must be positive and in the same unit. This is not an A-weighted sound-level meter and does not add a reference such as 1 pW or 10⁻¹² W/m².
P₁: Reference power or intensity.
P₂: Compared power or intensity, same unit as P₁.
Level (dB): 10 log₁₀(P₂ / P₁).
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