How to use the doppler effect calculator
Find the frequency heard by a moving observer or source. Enter source frequency, source speed (toward observer +), observer speed (toward source +), wave speed in the fields above; the observed frequency is computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “ambulance siren pitch”, “moving source frequency”, “approaching vs receding”, “calculate doppler effect”, “find observed frequency”.
Formula
Variables
- f — Source frequency (Hz)
- vs — Source speed (toward observer +) (m/s)
- vo — Observer speed (toward source +) (m/s)
- c — Wave speed (m/s)
Worked example
With source frequency = 500 Hz, source speed (toward observer +) = 30 m/s, observer speed (toward source +) = 0 m/s, wave speed = 343 m/s, the calculator gives observed frequency ≈ 547.9233 Hz.
Frequently asked questions
What is the doppler effect calculator used for?
Find the frequency heard by a moving observer or source. It helps with questions such as “ambulance siren pitch”, “moving source frequency”, “approaching vs receding”.
What is the formula for the doppler effect calculation?
Observed frequency (Hz) = f × (c+vo) / (c-vs). Here f is source frequency (Hz), vs is source speed (toward observer +) (m/s), vo is observer speed (toward source +) (m/s), c is wave speed (m/s).
What inputs do I need for the doppler effect calculator?
You need source frequency in Hz, source speed (toward observer +) in m/s, observer speed (toward source +) in m/s, wave speed in m/s. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the doppler effect calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the doppler effect result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.