Science & Engineering

Doppler Effect Calculator - Observed Frequency & Pitch Shift

Calculate the observed frequency of a moving sound source using the Doppler effect formula. Enter source frequency, velocities, and wave speed to compute the perceived frequency and pitch shift in semitones.

Source freq (Hz)

Source velocity (m/s)

Observer velocity (m/s)

Wave speed (m/s)

Positive velocity = approaching

Observed frequency

488.89 Hz

Pitch shift

+1.82 st

How it works

Blue circles: compressed (higher frequency ahead). Green circles: stretched (lower frequency behind).

Doppler Formula

f_obs = f_src × (v_wave + v_obs) / (v_wave − v_src)

Positive velocities indicate approach; negative velocities indicate recession. As the source approaches the observer the denominator decreases, raising the observed frequency.