About this tool
Convert between cents, frequency ratios and pitch detuning in your browser. Pick what you want to solve for: the cents between two frequencies, the frequency ratio for a given number of cents, or a detuned frequency from a base pitch plus a cents offset. It also reports the equivalent in semitones. Nothing is sent anywhere.
The core formula is cents = 1200 × log2(f2 / f1). Rearranged, a frequency ratio for a number of cents is 2^(cents / 1200), and a base frequency detuned by some cents becomes f × 2^(cents / 1200), with the hertz difference shown alongside. Because an equal-tempered semitone is exactly 100 cents, semitones = cents / 100.
For example, A4 at 440 Hz compared with 466.16 Hz is 100 cents, or one semitone. Use it to measure how flat or sharp two pitches are, set precise detune amounts on a synth or sampler, or convert a tuning ratio into cents.