Hz to Cent Converter
Calculate the interval in cents between any two frequencies using cents = 1200 × log₂(f₂ / f₁). Auto-identifies the closest just or equal-tempered interval (5:4 major 3rd, 3:2 perfect 5th, etc.), shows frequency ratio, and includes A/B audio comparison.
Input — Two Frequencies
Result
Just vs Equal-Tempered Interval Reference
| Interval | 12-TET (¢) | Just (¢) | Just ratio | Difference (¢) |
|---|---|---|---|---|
| Unison | 0 | 0 | 1:1 | 0 |
| Minor 2nd (semitone) | 100 | 111.73 | 16:15 | +11.73 |
| Major 2nd | 200 | 203.91 | 9:8 | +3.91 |
| Minor 3rd | 300 | 315.64 | 6:5 | +15.64 |
| Major 3rd | 400 | 386.31 | 5:4 | −13.69 |
| Perfect 4th | 500 | 498.04 | 4:3 | −1.96 |
| Tritone | 600 | 590.22 / 609.78 | 45:32 / 64:45 | −9.78 / +9.78 |
| Perfect 5th | 700 | 701.96 | 3:2 | +1.96 |
| Minor 6th | 800 | 813.69 | 8:5 | +13.69 |
| Major 6th | 900 | 884.36 | 5:3 | −15.64 |
| Minor 7th | 1000 | 996.09 | 16:9 | −3.91 |
| Major 7th | 1100 | 1088.27 | 15:8 | −11.73 |
| Octave | 1200 | 1200 | 2:1 | 0 |
About Cents & Frequency Intervals
The cent is a logarithmic measure of musical interval: cents = 1200 × log₂(f₂ / f₁). There are exactly 1,200 cents per octave, 100 cents per equal-tempered semitone, and the cent applies the same way at any base frequency — going from 100 Hz to 100.58 Hz is the same "musical distance" (10 cents) as going from 1,000 Hz to 1,005.78 Hz.
Why two-frequency intervals matter
Pure tuning intervals (just intonation) use simple integer ratios: 3:2 = perfect 5th, 5:4 = major 3rd, 6:5 = minor 3rd. These ratios produce maximally consonant sounds because the overtones align. Equal temperament (12-TET) tempers all intervals to a uniform semitone of exactly 100 cents — convenient for keyboards but slightly "wrong" compared to just intervals (a 12-TET major 3rd is 13.69 cents flat of the just 5:4 version).
Practical use cases
Choir directors use cents to analyse pitch drift across phrases. Studio engineers use it to tune samples and loops to a target. Microtonal composers use it to specify experimental scales (e.g., 24-TET quarter-tones, 19-TET, Bohlen-Pierce). Researchers use it to study cultural tuning traditions — gamelan, maqam, raga systems all use non-12-TET intervals best described in cents.
Interval names beyond an octave
For cents values above 1,200, this tool reduces them to a single-octave interval class plus the octave count. So 1,902 cents = "Just perfect 5th + 1 octave" (a "twelfth"). 2,400 cents = "Octave + 1 octave" = two-octave doubling.