Note Frequency Calculator

How to Use This Calculator

1. Select the note name (C, D, E, etc., including sharps/flats).
2. Enter the octave number (0-8, where middle C is C4).
3. The calculator displays the frequency in Hz (Hertz, cycles per second).
4. Use this for tuning instruments, understanding pitch, or audio engineering.

Note Frequency Formula

Frequency is calculated using equal temperament tuning:

Where A4 = 440 Hz. Example: C4 is 9 semitones below A4, so: Frequency = 440 × 2^(-9/12) = 261.63 Hz. C5 is 3 semitones above A4, so: Frequency = 440 × 2^(3/12) = 523.25 Hz.

Full Description

Every musical note corresponds to a specific frequency, measured in Hertz (Hz), which represents how many times per second the sound wave vibrates. Understanding note frequencies is essential for tuning instruments, audio engineering, and understanding the physics of sound. The standard tuning reference is A4 = 440 Hz, meaning the A note in the 4th octave vibrates at 440 cycles per second.

In equal temperament tuning (the standard for modern Western music), each semitone multiplies or divides the frequency by the 12th root of 2 (approximately 1.05946). This means each octave doubles or halves the frequency—C4 is 261.63 Hz, C5 is 523.25 Hz (exactly double), and C3 is 130.81 Hz (exactly half). This mathematical relationship creates the octave, which sounds like the same note at a different pitch.

This calculator helps you find the frequency of any note in any octave. Select the note and octave, and it calculates the frequency based on A4 = 440 Hz standard tuning. Use it for tuning instruments, understanding pitch relationships, audio engineering, or learning about the physics of sound. Understanding frequencies helps you work with audio equipment and understand how music relates to physics.

Frequently Asked Questions