Doppler Effect Calculator
Works out the shift in pitch as a sound source passes.
Frequency heard
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Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
Change —
Pitch ratio — ×
Wavelength in the air —
Reading this —
The formula
f′ = f × (c ± v_listener) ÷ (c ∓ v_source)
Use the upper signs when moving towards the other party. Moving towards each other raises the pitch.
What to watch out for
Speeds count relative to the air. Wind changes the result slightly.
Frequently Asked Questions
What does a 700 Hz siren sound like at 100 km/h?
About 762 Hz approaching and 648 Hz going away.
Is a moving listener the same as a moving source?
Not quite. At 30 m/s and 700 Hz, a moving source gives 767.1 Hz, and a moving listener gives 761.2 Hz.