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Doppler Effect Calculator

Calculate the frequency heard by a stationary observer as a sound source approaches, using the Doppler formula f′ = f × v / (v − vₛ).

Observed frequency
467.24Hz

Formula: f' = f × v / (v − vₛ)

About Doppler Effect Calculator

Doppler Effect Calculator is a free online calculator that gives you an instant, accurate result as you type. Calculate the frequency heard by a stationary observer as a sound source approaches, using the Doppler formula f′ = f × v / (v − vₛ).

The calculation uses the standard formula f' = f × v / (v − vₛ) and updates live with every change to the inputs. Everything runs client-side in your browser — fast, private, and free to use as often as you like.

The Doppler effect explains why an ambulance siren sounds higher-pitched as it approaches and suddenly drops as it passes you.

Frequently Asked Questions

Is Doppler Effect Calculator free to use?

Yes. Doppler Effect Calculator is completely free, with no sign-up, no downloads, and no usage limits. You can use it as many times as you like on any device with a web browser.

How accurate is this calculator?

The calculator applies the standard formula (f' = f × v / (v − vₛ)) with full floating-point precision and rounds only the displayed result. For most practical purposes the results are exact.

What if the source is moving away?

Enter the source speed as a negative number: the denominator becomes v + vₛ and the observed frequency drops below the emitted one.