Physics

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Beat Frequency Calculator.

Calculate the beat frequency between two tones.

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01

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beatFrequency: 2

beatFrequency

2.000000

Use Cases

Tuning musical instruments

Musicians can use beat frequency to tune instruments by listening for beats between a reference tone and the instrument's tone. A zero beat frequency indicates perfect tuning.

Example: If a tuning fork is 440 Hz and the piano string is 442 Hz, the beat frequency is 2 Hz.

Acoustic experiments

Physics students and educators can demonstrate wave interference by calculating beat frequencies from two sound sources.

Example: Two speakers emitting 300 Hz and 305 Hz produce a 5 Hz beat.

Frequently Asked Questions

What is beat frequency?
Beat frequency is the difference between two sound frequencies. When two tones with slightly different frequencies are played together, you hear a periodic variation in loudness, which is the beat. The beat frequency equals the absolute difference of the two frequencies.
How do I use this calculator?
Enter the first frequency and the second frequency in hertz (Hz) into the respective fields. The calculator will compute the absolute difference between them, which is the beat frequency.
What units should I use?
Both frequencies must be entered in hertz (Hz). The result will also be in hertz. Ensure both values are positive numbers.

Tips & Common Mistakes

Tips

  • Ensure both frequencies are in hertz (Hz) before entering them.
  • The beat frequency is always the absolute difference, so order doesn't matter.
  • For audible beats, the frequency difference should be less than about 20 Hz.
  • Use this calculator to quickly check tuning or experiment setups.

Common Mistakes to Avoid

  • Entering frequencies in different units (e.g., one in kHz and one in Hz) without converting.
  • Forgetting that beat frequency is the absolute difference, not the sum.
  • Using negative values or zero, which are not valid for frequencies.

Last updated: August 13, 2026