Musical Note to Frequency Calculator
Convert any musical note and octave to its frequency in Hz. Calculates wavelength, period, and supports custom A4 tuning reference for period and historical instruments.
Results
What is it?
In 12-tone equal temperament, every semitone is a frequency ratio of the 12th root of 2 (�1.05946). Starting from A4=440 Hz, any note frequency is calculated as: f = 440 � 2^(n/12), where n is the number of semitones from A4. This universal formula is the foundation of all modern Western music tuning.
How to use
Select a note, enter the octave (A4 = octave 4), and set the A4 reference frequency. Standard is 440 Hz; orchestras in Germany and Austria often use 442 Hz; Baroque ensembles use 415 Hz (exactly one semitone below A440). The calculator returns the precise frequency, its wavelength in air at 20�C (343.2 m/s), period, and MIDI note number.
Example scenario
Middle C (C4) is 9 semitones below A4. Frequency = 440 � 2^(-9/12) = 261.626 Hz. Its wavelength at 20�C = 343.2/261.626 = 131.2 cm (just over 4 feet). This matters for room mode calculations � a 4-foot room dimension resonates strongly at middle C.
Pro tip
The A4 = 432 Hz "432 Hz tuning" popular in some music communities has no scientific basis for healing properties but does slightly lower all frequencies. At 432 Hz, A4's wavelength = 343.2/432 = 79.4 cm. Use standard 440 Hz for recording with other musicians unless specifically working in an alternative tuning system.