Semitone calculator

Measure the equal-tempered interval between two frequencies, or apply a semitone shift to a starting frequency.

Pitch resultEnter values to calculate

An octave is a frequency ratio of two

Twelve equal-tempered semitones double a frequency. The interval formula uses a base-2 logarithm, so 440 Hz to 880 Hz is exactly 12 semitones or 1,200 cents.

Frequency math does not identify a note by itself

The result describes an interval. A note name also depends on the tuning reference and temperament used by the instrument or session.

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