Sound Pressure Level

This calculates the sound pressure level in dB from a known sound pressure in Pascals (Pa). The reference sound pressure default is 20 µPa (2×10-5 Pa or 0.00002 Pa) which is the threshold of human hearing. P = Sound Pressure (Pa) and Po is the Reference Sound Pressure (default 20 µPa). The result is expressed in dB.

Formula

  • \( SPL = 20 \log (P/P_o) \)
Variable Unit
SPL dB (sound pressure level)
P Pa (sound pressure in Pascals)
Po Pa (reference pressure, default 20 µPa = 2×10-5 Pa)

Sound Pressure Level

\( SPL = 20 \log (P/P_o) \)
SPL
dB = 20 * Log (
P
/
Po
)

Digits of Precision:

Pa
Pa