Sound Level (dB) Calculator

Convert ratios to decibels and estimate sound pressure level (SPL). Useful for audio and acoustics basics.

Choose what you want to calculate.
Enter a value.
If you enter both, we use ratio = A/B.
Good for testing that buttons work.
Power: dB = 10·log₁₀(P₂/P₁)
Amplitude: dB = 20·log₁₀(A₂/A₁)
SPL: dB = 20·log₁₀(p/p₀), p₀ = 20 µPa
Ratios must be positive.
+3 dB ≈ 2× power
+10 dB = 10× power
+6 dB ≈ 2× amplitude
These are approximations.