Doppler Effect Calculator

What this tool does

The two results are the drop you hear as an ambulance passes: the first is the approaching pitch, the second is the receding one, and the jump between them happens in the instant it goes by. The semitone figure puts that shift in musical terms — a passing siren often drops more than a whole tone.

Formula

f′ = f × (c + v observer) ÷ (c − v source)

Variables

Worked example

Limitations

• The formula assumes ideal conditions: no friction losses, no air resistance and no efficiency losses unless you enter them.
• The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.