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Doppler Effect Calculator

Observed frequency shift from relative motion.

Introduction

Doppler Effect Calculator — Observed frequency shift from relative motion. Enter Source frequency (Hz), Sound speed (m/s), Observer velocity (m/s), Source velocity (m/s), Motion to get an instant, accurate result.

Formula

The acoustic Doppler effect is calculated as f' = f × (v ± v_observer) / (v ± v_source), where f is the emitted source frequency, v is the speed of sound in the medium, and the signs depend on whether the source and observer are moving toward or away from each other.

Step-by-step

  1. Enter the Source frequency (Hz).
  2. Enter the Sound speed (m/s).
  3. Enter the Observer velocity (m/s).
  4. Enter the Source velocity (m/s).
  5. Enter the Motion.
  6. Click Calculate to see your result instantly.

Real-world example

Example: With Source frequency (Hz) = 1000, Sound speed (m/s) = 340, Observer velocity (m/s) = 0, Source velocity (m/s) = 30, Motion = 1, the Doppler Effect Calculator gives Observed Frequency Hz: 1096.7742.

Frequently Asked Questions

What is the Doppler effect?
The Doppler effect, named after Austrian physicist Christian Doppler, describes how the observed frequency of a wave changes when the source and observer are moving relative to each other — higher when approaching, lower when receding.
What is a real-world example of the Doppler effect?
A classic example is the changing pitch of a siren as an ambulance passes by: the pitch sounds higher as it approaches and lower as it moves away, due to compression and stretching of sound waves.
What speed of sound does this calculator use?
The speed of sound in air is approximately 343 m/s at 20°C, though this can be adjusted for different temperatures or mediums since sound travels at different speeds through different materials.
What inputs does the Doppler Effect Calculator need?
You'll need to provide: Source frequency (Hz), Sound speed (m/s), Observer velocity (m/s), Source velocity (m/s), Motion. All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the Doppler Effect Calculator?
The Doppler Effect Calculator applies the formula exactly as calculated — The acoustic Doppler effect is calculated as f' = f × (v ± v_observer) / (v ± v_source), where f is the emitted source frequency, v is the speed of sound in the medium, and the signs depend on whether the source and observer are moving toward or away from each other. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the Doppler Effect Calculator free to use?
Yes, the Doppler Effect Calculator is completely free, requires no signup, and runs instantly in your browser.

About the Doppler Effect Calculator

The Doppler Effect Calculator uses a real, verifiable formula — The acoustic Doppler effect is calculated as f' = f × (v ± v_observer) / (v ± v_source), where f is the emitted source frequency, v is the speed of sound in the medium, and the signs depend on whether the source and observer are moving toward or away from each other. — so results are accurate every time, not an approximation.