How to Calculate Note Frequencies

• The reference standard for the frequency of the notes is usually the A note in octave 4 at 440Hz.
• Since each octave is double the frequency of the previous octave the A notes in each octave are

• Note that the range of human hearing is about 20 to 20 000 Hz. so we didn't need to go any further on the frequency range.
• What about the notes between the A's. Our first instinct may be to equally increment the notes. For example in the 4th octave between 440 and 880 Hz., just take the difference 880-440=440 and divide by 12. 440/12=36.67. Perhaps we could equally divide the notes by 36.67 Hz between the A's. Of course this would not work, what if we wanted to play in the key of C major, there would be a different increment between the notes from C to A than there would be from A to B. This surely could not sound correct. In fact the musical note scale is exponential. For an explanation of exponential data see Exponential Data Explained - (Logarithms)
• Note that

• What about the notes between the A's. ......Use the following

• Example D is a note 5 notes higher than A4

• Example 2 The d one octave lower would be 7 notes below A4

• You can calculate any note frequency using this equation.