Doppler Effect

Calculate the frequency a moving observer hears from a moving sound source, free online.

Source frequency (Hz)

Source speed toward observer (m/s)

Observer speed toward source (m/s)

Speed of sound (m/s)

About this calculator

The observed frequency is f′ = f × (v + v_o) ÷ (v − v_s), where v is the speed of sound (343 m/s in air), v_o is the observer's speed toward the source and v_s the source's speed toward the observer. Use negative values for motion away.