Note Frequency
Calculate the frequency of any musical note in the equal temperament scale. Free note frequency converter with Hz, wavelength, MIDI number, and harmonic series chart.
About This Calculator
The Note Frequency Calculator converts any musical note in the twelve-tone equal temperament system to its exact frequency in Hertz (Hz), wavelength in meters, and MIDI note number. Musicians, audio engineers, music producers, and physics students use this tool to understand the relationship between pitch, frequency, and wavelength.
In the equal temperament system — the most common tuning system since the 18th century — each semitone is exactly the 12th root of 2 apart. The calculator uses the standard formula f = 440 × 2(n‑69)/12, where n is the MIDI note number. A4 (the A above middle C) is defined as 440 Hz per ISO 16. The harmonic series chart visualises the first 8 overtones — integer multiples of the fundamental frequency that give every instrument its unique timbre and colour.
How to use
Select a note (C through B) and an octave (0 to 8) from the dropdown menus, then click Calculate. The tool displays the frequency in Hz, wavelength (at 20°C, 343 m/s), MIDI note number, scientific pitch notation (e.g. A4), angular frequency, and period. The harmonic series chart shows the first 8 harmonics in bar or pie mode.
Note Frequency Chart References
Standard frequencies for common reference pitches: C0 = 16.35 Hz (lowest piano note), C4 (middle C) = 261.63 Hz, A4 = 440 Hz (standard tuning), C8 = 4186.01 Hz (highest piano note). The hearing range of a young human is roughly 20 Hz to 20,000 Hz.
Frequently Asked Questions
How do I calculate the frequency of a musical note?
Select a note name (C through B) and an octave (0 to 8), then click Calculate. The tool uses the equal temperament formula f = 440 × 2^((n-69)/12) where n is the MIDI note number to compute the exact frequency in Hertz.
What is the formula for note frequency?
The formula for note frequency in twelve-tone equal temperament is f = 440 × 2^((n-69)/12), where n is the MIDI note number, 440 is the frequency of A4 in Hertz, and 69 is the MIDI number for A4.
What is the frequency of A4?
A4 (the A above middle C) has a standard frequency of 440 Hz. This is the international tuning standard ISO 16 used by most orchestras and musicians worldwide.
How is the wavelength of a note calculated?
Wavelength is calculated using the formula λ = v / f, where v is the speed of sound (approximately 343 m/s at 20°C) and f is the frequency in Hertz. For example, A4 at 440 Hz has a wavelength of about 0.78 meters.
What are harmonics in music?
Harmonics are integer multiples of a note's fundamental frequency. The 1st harmonic is the fundamental, the 2nd is twice the frequency, the 3rd is three times, and so on. These overtones give each instrument its unique timbre.
What is MIDI note numbering?
MIDI note numbers assign each pitch an integer from 0 to 127. Middle C (C4) is MIDI note 60, and A4 is MIDI note 69. The formula for MIDI note number is (octave + 1) × 12 + note index, where C=0, C#=1, ..., B=11.
Is this note frequency calculator free?
Yes, this note frequency calculator is completely free to use with no registration or hidden charges. You can bookmark or share your calculation via URL.