About the Doppler Effect Calculator
Observed frequency when a source or observer is moving — the Doppler shift for sound.
Also known as: doppler shift, frequency shift, moving source frequency.
How to use this calculator
- Enter source frequency, source speed (+ towards observer), observer speed (+ towards source), speed of sound.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Doppler Effect formula
f' = f (c + v_observer) / (c − v_source)
Worked example
Using the values pre-filled in the calculator above:
- Source frequency = 500 Hz
- Source speed (+ towards observer) = 30 m/s
- Observer speed (+ towards source) = 0 m/s
- Speed of sound = 343 m/s
the calculator returns:
- Observed frequency: 547.92 Hz
- Frequency shift: 47.92 Hz
- Percentage shift: 9.58%
- Observed wavelength: 0.626 m