Sound Pressure Level Calculator — Pa to dB SPL
Convert between sound pressure in pascals and SPL in decibels. Reference: 20 µPa (threshold of hearing).
Enter pressure in pascals
How We Calculate This
SPL (dB) = 20 × log10(P / P_ref)
Where P is the sound pressure in pascals and P_ref is 20 × 10⁻⁶ Pa (20 µPa).
P = P_ref × 10^(SPL/20)
The factor of 20 (not 10) is used because SPL is a field quantity (pressure), not a power quantity.
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates based on standard formulas. Always verify results for critical applications.