Calculate the number of octaves between two frequencies, find the frequency any number of octaves above or below, or get octave band limits in Hz.

Result unit

Octaves from Frequency Formula

Octave span is the base-2 logarithm of the upper-to-lower frequency ratio. Use positive frequencies in compatible units. The band modes use exact base-2 fractional octaves.

O = log (Fu / Fl) / log (2)

Variables:

  • #O is the Octaves from Frequency (number of octaves)
  • Fu is the upper frequency (Hz) 
  • Fl is the lower frequency (Hz) 

How to Calculate Octaves from Frequency?

The following steps outline how to calculate the Octaves from Frequency.

  1. First, determine the upper frequency (Hz). 
  2. Next, determine the lower frequency (Hz). 
  3. Next, gather the formula from above: #O = log (Fu/Fl) / log (2).
  4. Finally, calculate the Octaves from Frequency.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

upper frequency (Hz) = 50

lower frequency (Hz) = 30

O = log(50/30) / log(2) ≈ 0.736966 octaves.