Doppler Effect Calculator

Calculate the observed frequency when a sound source and observer are in relative motion using the Doppler effect equation.

Inputs

Source Frequency

Source Velocity

m/s

Observer Velocity

m/s

Speed of Sound

m/s

Tab to move between fields

Results

Observed Frequency

404.61 Hz

Frequency Shift-35.39 Hz

Percent Shift-8.04%

Source Wavelength0.78 m

Observed Wavelength0.85 m

How to Use This Calculator

Enter Source Frequency, Source Velocity, and Observer Velocity.
Set Speed of Sound.
Review the Observed Frequency (Hz) result.
Use Frequency Shift (Hz) and Percent Shift (%) to inform your decision.
Use the chart to visualize the results and explore different scenarios by adjusting inputs.

How the result changes with Source Frequency

Source Frequency	Observed Frequency
10,001	9,196.63 Hz
35,001	32,185.91 Hz
65,000	59,772.12 Hz
90,000	82,761.39 Hz

What each input means

Source Frequency: Frequency emitted by the source. Concert A = 440 Hz.
Source Velocity: Velocity of the source. Positive = moving away from the observer, negative = approaching.
Observer Velocity: Velocity of the observer. Positive = moving toward the source, negative = moving away.
Speed of Sound: Speed of sound in the medium. Air at 20°C ≈ 343 m/s, water ≈ 1480 m/s.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Source Frequency = 440, Source Velocity = 30, Observer Velocity = 0, Speed of Sound = 343 = 4 input(s) provided
Calculate Observed Frequency
Observed Frequency
404.61 = 404.61
Calculate Frequency Shift
Frequency Shift
-35.39 = -35.39
Calculate Percent Shift
Percent Shift
-8.04 = -8.04

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