Enter any two notes to find the interval name and semitone distance between them.
Calculator verified • Last updated: August 2026
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An interval is just the distance between two pitches, measured in semitones. Each note is first converted to a MIDI note number (middle C, or C4, is MIDI 60), and the interval is the difference between the two numbers. That semitone count then maps directly onto a standard interval name — 7 semitones is always a Perfect 5th, 4 semitones is always a Major 3rd, and so on, regardless of which two specific notes produced that distance.
C4 is MIDI 60 and G4 is MIDI 67, so the distance is 67 − 60 = 7 semitones. 7 semitones is the Perfect 5th — the same interval whether it's C to G, D to A, or any other pair of notes 7 semitones apart. This is also the interval between the first two notes of "Twinkle, Twinkle, Little Star" and the famous opening of the "Star Wars" theme.
Unisons, 4ths, 5ths, and octaves are called "Perfect" because their ratio to the root note stays acoustically stable and consonant across both major and minor scales — a perfect 5th sounds the same interval quality whether you're in a major or minor key. 2nds, 3rds, 6ths, and 7ths instead come in "Major" and "Minor" versions that differ by exactly one semitone, because their sound genuinely changes character between major and minor contexts (a major 3rd sounds bright, a minor 3rd sounds darker) — this naming split traces back to medieval and Renaissance music theory's classification of consonant versus mutable intervals.
A distance of more than 12 semitones (a compound interval) is described as a certain number of semitones past one or more full octaves, plus the simple interval name of the remainder — 19 semitones, for instance, is 12 (one octave) plus 7, so it's reported as a Perfect 5th an octave up. This matters for vocal range and instrument range questions, where the notes being compared often span more than one octave.
Counting letter names (C, D, E...) instead of semitones is the most common error — "C to E" looks like a 3rd by letter-counting, but whether it's 3 semitones (a Minor 3rd, as in C to Eb) or 4 semitones (a Major 3rd, as in C to E) depends entirely on the accidentals involved, not the letter names alone. Another frequent mix-up: forgetting that interval quality (Perfect/Major/Minor) depends only on the semitone count, not on which of the two notes was entered first — reversing the note order flips the sign of the distance but not the interval name.
Interval — the distance in pitch between two notes, most precisely measured in semitones.
MIDI Note Number — a standard integer numbering of every pitch (middle C = 60), used to compute pitch distances consistently.
Semitone — the smallest standard interval in Western tuning; the distance between any key and the very next one on a piano.
Compound Interval — any interval spanning more than one octave (more than 12 semitones), described as an octave plus a simple interval.
There's no such thing as a "Major 5th" in standard interval naming — unisons, 4ths, 5ths, and octaves are always called "Perfect" (or, less commonly, augmented/diminished), while 2nds, 3rds, 6ths, and 7ths use "Major"/"Minor." This calculator always reports the standard name for each semitone distance.
The interval name is the same either way (C4 to G4 and G4 to C4 are both a type of 5th), but the signed semitone distance flips sign depending on which note you enter first — this calculator always tells you which of your two notes is higher.
The calculator still reports it, describing it as a certain number of semitones beyond one or more full octaves plus the interval name of the remainder — for example, 19 semitones is reported as 7 semitones beyond an octave (Perfect 5th + octave), since 19 = 12 + 7.