Doppler Effect Calculator
Observed frequency for a moving source.
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Results update instantly as you type — no submit needed.
Results
- Observed frequency
- 467.24 Hz
- Frequency shift
- 27.24 Hz
- Percentage shift
- 6.19%
- Semitones shift
- 1.04
Quick answer
The Doppler effect raises observed frequency when a source approaches and lowers it as it recedes.
f' = f(v ± vo) ÷ (v ∓ vs)
How to use the Doppler Effect Calculator
- 1Enter the source's true frequency.
- 2Enter source and observer speeds.
- 3Choose whether the source approaches or recedes.
Frequently asked questions
Why does a siren drop in pitch?
As it passes, the source switches from approaching to receding.
Does light Doppler shift too?
Yes — that is redshift, though it needs relativistic formulas.