Music · Tuning
Note frequency and cents calculator.
Three tuning conversions in one place: note name to hertz, hertz to the nearest note with its cents offset, and the interval in cents between two frequencies.
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How do you convert Hz to a note and cents?
Twelve-tone equal temperament divides the octave into 12 semitones of 100 cents each, so an octave is 1,200 cents. For two frequencies the interval is cents = 1200 × log2(f2 / f1), and going back, f2 = f1 × 2cents / 1200. To find the nearest note, round 69 + 12 × log2(f / A4) to the nearest whole MIDI number, then take the cents from that note.
Worked example. A tone at 445 Hz with A4 = 440: the nearest note is A4, and the offset is 1200 × log2(445 / 440) = +19.56 cents (sharp). Between 440 and 452 Hz the interval is 46.58 cents. The general formula is cents = 1200 × log2(f2 / f1).
How big is a cent? A single cent is too small to be perceived between successive notes. One author stated that humans can distinguish a difference in pitch of about 5 to 6 cents, and the threshold varies with frequency, loudness and timbre. A tuner showing within a few cents is in tune for most purposes.
Frequently asked questions
What is a cent in music?
One hundredth of an equal-tempered semitone. There are 100 cents in a semitone and 1,200 in an octave.
How do I convert Hz to cents?
Cents = 1200 x log2(f2 / f1) between two frequencies. For a tuner offset, f1 is the frequency of the target note.
What is the frequency of A4?
440 Hz by the usual standard. This calculator lets you set the reference from 400 to 480 Hz, for example 442 Hz.
What is the note for 445 Hz?
A4, about 19.6 cents sharp when A4 is 440 Hz.
Can humans hear a 5 cent difference?
Barely. About 5 to 6 cents is cited as the size of a pitch difference people can distinguish, and it varies by frequency, loudness and timbre.
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