Octave Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserBasic
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the two frequencies.
- Read the octaves and cents apart.
How it works
Octaves = log₂(frequency 2 ÷ frequency 1); one octave = 1200 cents.
Worked example
440 Hz to 880 Hz. = 1 octave (1200 cents).
Common mistakes
- Thinking an octave is a fixed number of hertz — it's a doubling ratio.
- Swapping the two frequencies (gives a negative result).
Frequently asked questions
What's a cent?
1/100th of a semitone, or 1/1200th of an octave — the standard fine measure of pitch difference.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.