ONE FORMULA, ONE ANSWER
Sound Pressure Level Calculator
Calculate sound pressure level relative to an explicit reference pressure. Choose input units and calculate one value within the stated conditions.
Inputs
Calculations run in this browser. Scientific notation such as 1.2e-3 is supported. Do not group thousands.
Result
Sound pressure level L_p
Enter values and select Calculate.
L_p = 20 log₁₀(p_rms/p_ref)
Assumptions
Required: positive RMS and reference pressures. The air example uses 20 μPa; other environments may use another reference. A-weighting, hearing effects, power ratios and noise exposure are excluded.
Displayed values are floating-point approximations. Design safety factors and unprovided error contributions are not calculated.
Formula references and credits
NaNa Lab created the code, descriptions, icons and preview images. Text, figures and code from the linked references have not been reproduced.
Physical constants: NIST / CODATA 2022. The values of μ₀ and ε₀ are measured recommendations, not exact defining constants. Values and precision notes are in the source record.
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