SPL a partir de pressão
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
This calculator converts sound pressure into Sound Pressure Level (SPL), using the formula SPL = 20·log₁₀(p/p₀), where p₀ = 20 μPa. SPL is a logarithmic measure representing sound intensity relative to a reference pressure. It's widely used in acoustics, noise studies, and audio engineering.
To use the calculator, input the sound pressure value (p) in pascals. The calculation compares it to the human hearing threshold (20 μPa). Results in decibels (dB) reflect perceived loudness. Prolonged exposure to sounds above 85 dB can cause hearing damage.
Ensure input pressure is in micropascals (μPa) or correctly converted. Calculations assume measurements in air, not other mediums. For complex sounds or environments with reflections, additional adjustments may be necessary.
Frequently asked questions
What is SPL?
SPL (Sound Pressure Level) measures sound intensity in decibels (dB) using a reference pressure of 20 μPa, the human hearing threshold.
Why is 20 μPa the reference value?
20 μPa represents the lowest sound pressure detectable by the human ear, providing a baseline for comparing all other sound levels.
How does the calculator process input pressure?
It applies the formula SPL = 20·log₁₀(p/p₀), converting pressure directly into a logarithmic scale. Results in dB reflect sound perception.
Do I need to convert units before using the calculator?
Yes, pressure must be in micropascals (μPa). If input is in pascals, convert by multiplying by 1,000,000.
Can this calculator be used for sounds in other media, like water?
No, the reference pressure (20 μPa) is specific to air. For other media, use appropriate reference values, such as 1 μPa for fresh water.