Doppler Effect Calculator
〰 Oscillations & waves. Use the Doppler effect (moving source) formula to find frequency you hear, frequency emitted, speed of sound, source speed: pick the value you want, type the others, and the answer updates as you go.
v_s positive when the source comes towards you (higher pitch), negative when it goes away.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Frequency you hear | Hz |
| Frequency emitted | Hz |
| Speed of sound | m/s |
| Source speed | m/s |
Worked example
Find the frequency you hear when Frequency emitted = 700 Hz, Speed of sound = 343 m/s, Source speed = 15.4 m/s.
Using f' = f v/(v - vs): Frequency you hear = 732.91 Hz.
Frequently asked questions
What is the formula for Doppler effect (moving source)?
f' = f v/(v - vs). v_s positive when the source comes towards you (higher pitch), negative when it goes away.
What do the letters stand for, and what units are used?
Frequency you hear in Hz, Frequency emitted in Hz, Speed of sound in m/s, Source speed in m/s.
How do you calculate frequency you hear?
Put the values into f' = f v/(v - vs). For example, with Frequency emitted = 700 Hz, Speed of sound = 343 m/s, Source speed = 15.4 m/s, frequency you hear = 732.91 Hz.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (frequency you hear, frequency emitted, speed of sound, source speed) and fill in the others: it rearranges the formula for you.
