How do I convert dB to Pascals?

p = p_ref × 10^(SPL/20), where p_ref = 20 μPa (= 2×10⁻⁵ Pa), the threshold of hearing.

What is the reference pressure for dB SPL?

The reference sound pressure is 20 μPa (micropascals) or 2×10⁻⁵ Pa, corresponding to the approximate threshold of human hearing at 1 kHz.

A-weighting adjusts measured sound levels to approximate human hearing sensitivity. It reduces low ( 6 kHz) frequencies. dBA is the A-weighted unit. Because the correction is frequency-dependent, a single dB(A) value cannot be converted to sound pressure in Pa without knowing the frequency spectrum — this converter works with unweighted dB SPL only.

0 dB SPL corresponds to a pressure of 20 μPa — the approximate threshold of human hearing. It is not silence, but the quietest sound most people can detect.

What is the pain threshold in dB?

The pain threshold is approximately 130–140 dB SPL, corresponding to about 63–200 Pa of sound pressure.

Free Engineering Tool #216

Sound Level Converter

Convert between unweighted sound pressure level (dB SPL) and sound pressure (Pa). Enter a value in either unit and get an instant conversion. Note: A-weighted levels in dB(A) are not directly convertible to Pa.

SPL = 20·log₁₀(p/p₀)dB SPL ↔ PaUnweighted

Results

Sound Pressure

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dB SPL

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Sound Pressure

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Sound Pressure Level

where p₀ = 20 μPa = 2 × 10⁻⁵ Pa (threshold of hearing)

A Note on dB(A)

This converter works with unweighted sound pressure levels (dB SPL). An A-weighted level, dB(A), applies a frequency-dependent correction curve that approximates human hearing sensitivity. Because the correction varies with frequency, a single dB(A) value cannot be converted to sound pressure in Pa without knowing the frequency spectrum of the sound. Do not enter dB(A) readings into this tool expecting an exact pressure value.

Common Sound Levels

Level (dB)	Pressure (Pa)	ឧទាហរណ៍
0	0.00002	Hearing threshold
30	0.00063	Quiet room
60	0.02	Normal conversation
85	0.36	Heavy traffic
94	1.0	1 Pascal reference
120	20.0	Pain threshold
140	200.0	Jet engine (close)