Beat Frequency Calculator
Find the beat frequency produced when two sound waves of slightly different frequencies interfere with each other.
What beat frequency is
When two sound waves with slightly different frequencies play together, they interfere and create a periodic rise and fall in loudness called a beat. The beat frequency equals the absolute difference between the two source frequencies: fbeat = |f1 – f2|.
How this calculator works
Enter the two frequencies being played (for example, two guitar strings or tuning forks). The calculator subtracts them to give the beat frequency, which is the rate at which you’ll hear the volume pulse, and also reports the average of the two frequencies, which is roughly the pitch you perceive.
Musicians commonly use beats to tune instruments — as two notes get closer in pitch, the beat frequency slows down until it disappears at perfect unison. This calculator is for general educational and planning purposes.