Pressure Amplitude Calculator

Calculator Inputs

Choose a method, enter values with units, then calculate pressure amplitude and supporting acoustic metrics.

Calculation mode

Medium density

Density unit

Sound speed

Speed unit

Particle velocity amplitude

Velocity unit

Bulk modulus

Bulk modulus unit

Wavenumber

Wavenumber unit

Displacement amplitude

Displacement unit

Acoustic intensity

Intensity unit

Reference pressure (Pa)

Output pressure unit

Plotly Graph

This chart compares amplitude, RMS pressure, and sound pressure level from the current calculation.

Example Data Table

This sample table shows typical inputs and resulting pressure amplitudes for different acoustic scenarios.

Case	Method	Density (kg/m³)	Speed (m/s)	Main Input	Pressure Amplitude (Pa)
Air wave	Velocity	1.225	343	u = 0.020 m/s	8.404
Lab signal	Intensity	1.225	343	I = 0.001 W/m²	0.917
Liquid test	Displacement	1000	1480	B = 2.2 GPa, k = 12, s = 0.2 µm	5280.000

Formula Used

The calculator supports three standard acoustic relationships for pressure amplitude. Each mode helps when different wave measurements are available.

1) From particle velocity amplitude

p_max = ρcu_max

Use this when medium density, sound speed, and particle velocity amplitude are known.

2) From displacement amplitude

p_max = Bks_m

Use this when bulk modulus, wavenumber, and particle displacement amplitude are known.

3) From intensity

p_max = √(2ρcI)

Use this when acoustic intensity is known and the wave is approximated as plane harmonic propagation.

Additional outputs

RMS pressure: p_rms = p_max / √2
Sound pressure level: SPL = 20 log₁₀(p / p_ref)
Acoustic impedance: Z = ρc

How to Use This Calculator

Select the calculation mode that matches your available acoustic data.
Enter medium properties such as density and sound speed where required.
Input velocity amplitude, displacement amplitude, or intensity with units.
Choose the desired output pressure unit.
Set the reference pressure if you need custom sound pressure levels.
Press the calculate button to display the result above the form.
Review the generated metrics, table, and Plotly graph.
Export the results as CSV or PDF when needed.

FAQs

1. What is pressure amplitude in sound waves?

Pressure amplitude is the maximum pressure variation above or below ambient pressure during a sound wave cycle. It describes wave strength and directly affects sound pressure level.

2. When should I use the velocity method?

Use the velocity method when particle velocity amplitude is known. It is common in acoustic theory, transducer analysis, and wave propagation problems where medium properties are available.

3. Why does the calculator show RMS pressure too?

RMS pressure is useful because many acoustic measurements and power relations depend on effective pressure, not peak pressure. It also helps compare calculated values with instrument readings.

4. What reference pressure should I use?

For air acoustics, 20 µPa is the common reference pressure. In other media or specialized studies, a different reference may be used for sound pressure level calculations.

5. Can this calculator be used for liquids?

Yes. Enter the appropriate density, sound speed, or bulk modulus for the liquid. Results depend heavily on correct medium properties and consistent unit selection.

6. What does acoustic impedance mean here?

Acoustic impedance equals density times sound speed. It indicates how strongly a medium resists particle motion when pressure changes pass through it.

7. Why are there multiple formulas for pressure amplitude?

Different experiments measure different wave quantities. Some provide intensity, some displacement, and others particle velocity. Each valid formula connects those measurements to pressure amplitude.

8. Does the calculator handle unit conversions automatically?

Yes. The calculator converts supported units into base SI values before computing results. This reduces manual conversion errors and speeds up acoustic calculations.