Doppler Effect Calculator

Doppler Effect Calculator

Computes the frequency an observer hears when the source, the observer, or both move, for sound in a medium.

Read the full guide to this tool

Source frequency (Hz)

Wave speed in the medium (m/s) Sound in air ≈ 343 m/s at 20 °C.

Source speed (m/s)

Observer speed (m/s)

Relative motion

Notes

Approaching motion raises the pitch, receding lowers it; the classic falling-siren effect as it passes.
If the source reaches the wave speed the formula breaks down: that is the sonic-boom shock front.