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· Last updated：2026-08-01
Convert sound pressure between linear units (Pa, µPa, µbar, mbar) and the decibel sound pressure level dB SPL (Lp = 20·log₁₀(p / 20 µPa), reference p₀ = 20 µPa = 2e-5 Pa RMS, per ISO 1683). Supports bidirectional linear↔logarithmic conversion. Calibration anchor: 1 Pa → 20·log₁₀(1/2e-5) ≈ 94 dB SPL. Reference values: threshold of hearing 20 µPa (0 dB), speech ≈ 0.02 Pa (60 dB), rock concert ≈ 20 Pa (120 dB), pain threshold ≈ 200 Pa (140 dB).
Execution
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Tool usage guide
Convert sound pressure between Pa, µPa, µbar, mbar, and dB SPL referenced to 20 µPa. Enter a value, choose the input and output units, and set the desired decimal places for a clear JSON result.
Background
An audio technician needs to verify a microphone calibration point expressed as 1 Pa.
Problem
Convert the linear pressure value into the corresponding dB SPL level.
How to use
Set Input unit to Pa, enter 1, set Output unit to dB SPL, and choose 2 decimal places.
{"inputUnit":"Pa","value":1,"outputUnit":"dB SPL","decimalPlaces":2}Outcome
The result is 93.98 dB SPL, commonly rounded to 94 dB SPL.
Background
An acoustics student wants to express a typical speech reference of 60 dB SPL as linear sound pressure.
Problem
Convert the logarithmic SPL value into pascals for comparison with linear measurements.
How to use
Set Input unit to dB SPL, enter 60, set Output unit to Pa, and choose 8 decimal places.
It uses 20 µPa, equal to 2e-5 Pa RMS, as the dB SPL reference pressure.
1 Pa is approximately 93.98 dB SPL, commonly rounded to 94 dB SPL.
Yes. Select dB SPL as the input unit and Pa as the output unit.
The converter supports Pa, µPa, µbar, mbar, and dB SPL.
Linear pressure values must be non-negative. dB SPL inputs must be finite numbers.
{"inputUnit":"dB SPL","value":60,"outputUnit":"Pa","decimalPlaces":8}Outcome
The result is 0.02 Pa, equivalent to 20,000 µPa and 0.2 µbar.