Micropascal (µPa)
One millionth of a pascal. The reference sound pressure in water is 1 µPa.
What is a micropascal?
- Symbol
- µPa
- Quantity
- Sound Pressure Level (dB SPL)
- Unit system
- SI
- Definition
- One millionth of a pascal. The reference sound pressure in water is 1 µPa.
- Exact
- Yes, the value is exact by definition
- Source
- SI Brochure, 9th edition (BIPM, 2019)
Common applications
The reference unit of acoustics: 20 µPa is the reference pressure in air (0 dB SPL) and 1 µPa is the reference in water.
Micropascal in other sound pressure level (db spl) units
- 1 µPa = 0.000001 PaPascal
- 1 µPa = 0.001 mPaMillipascal
- dB SPL = 20 × log₁₀(µPa ÷ 20)Micropascal to Decibel SPL (re 20 µPa) converter
- dB re 1 µPa = 20 × log₁₀(µPa)Decibel re 1 µPa (underwater)
Micropascal quick reference
| Micropascal | Decibel SPL (re 20 µPa) | Pascal | Millipascal |
|---|---|---|---|
| 1 µPa | ≈ -26.02059991 dB SPL | = 0.000001 Pa | = 0.001 mPa |
| 20 µPa | = 0 dB SPL | = 0.00002 Pa | = 0.02 mPa |
| 200 µPa | = 20 dB SPL | = 0.0002 Pa | = 0.2 mPa |
| 2000 µPa | = 40 dB SPL | = 0.002 Pa | = 2 mPa |
| 20000 µPa | = 60 dB SPL | = 0.02 Pa | = 20 mPa |
| 200000 µPa | = 80 dB SPL | = 0.2 Pa | = 200 mPa |
Where the micropascal fits
The next larger sound pressure level (db spl) unit is the millipascal (mPa). 1 µPa = 0.001 mPa, and 1 mPa = 1000 µPa.