Interval Calculator & Transposer

Find the interval between any two notes — its name, size in semitones and cents, and direction — or transpose a note up or down by a set number of semitones.

Interval between two notes

Transpose a note

How it works

An interval is a distance in semitones, plus a name that depends on how the notes are spelled.

semitones = |midi_a - midi_b|

unison 0 · m2 1 · M2 2 · m3 3 · M3 4 · P4 5
tritone 6 · P5 7 · m6 8 · M6 9 · m7 10 · M7 11 · octave 12

Spelling matters: C to D♯ and C to E♭ are both three semitones, but the first is an augmented second and the second a minor third.

Worked example

• C4 (MIDI 60) to G4 (67) = 7 semitones = perfect fifth
• C4 to E♭4 (63) = 3 semitones = minor third
• C4 to F♯4 (66) = 6 semitones = tritone
• Transposing C4 up a perfect fourth = 60 + 5 = MIDI 65 = F4

In practice

• Intervals invert to nine. A third inverts to a sixth, a fourth to a fifth — and major becomes minor. Useful for working out voicings quickly.
• The tritone is its own inversion, which is why it is so unstable and so useful for modulation.
• Learn intervals by song. Perfect fifth: the opening of Twinkle, Twinkle. Minor third: a doorbell. It is faster than counting.
• In code, work in semitones and convert to names only for display. Pitch-class arithmetic is modulo 12.

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